The good news is that these cuffs are genuine.
The bad news (besides the fact that this is a long post) is that the winning bidder should not expect that they will be able to open the left cuff (as pictured in the first photo) when their belated Easter present arrives in the mail. It might be able to be opened, but I doubt it because of the following.
These cuffs are like a plug-8 in that there is a male course threaded plug on each of the movable bows, which thread into a female (cylindrical) locking piece having a male bolt on the opposite end (these are made from one piece of steel). The male bolt end has a spring-loaded brass (silver or nickel plated) cylinder that covers the bolt (same as the Rankin cuff, which should not be too surprising since these cuffs were made by A. Rankin Co., Philadelphia). These can be seen in the last photo posted (#10).
The one-piece cylinder/bolt is free-floating inside of the lockcase, and it is turned clockwise to tighten and counterclockwise to loosen. The key has an outer cylinder (with wing-nut for turning) and an inner bolt that threads through the outer cylinder (two-piece or "key within a key") and also has a wing-nut for turning. When the cuff is locked the outer key is threaded over the bolt in the lockcase (same as a Rankin) by turning the wing-nut until it bottoms out, and then the inner key is threaded down onto the end of the bolt creating the frictional force needed to turn the key and locking bolt together counterclockwise until the bow is threaded outward and unlocked.
The important thing to note is that the key cannot be removed from the lock when the cuff is opened because the locking bolt turns freely with the key and the key will not unthread. Hence the cuffs must be locked using the key in the reverse order as described above, and then the key can be removed when the bow is tightened against the frame (locked closed).
So, the reason I believe the left-hand cuff is not likely to be able to opened is because it is in a partially opened (about 1/16 inch) condition, which means that under normal (proper) operating condition the key would not have been able to be withdrawn from the locking bolt. Remember, the key can only be removed when the cuff is closed tight, unless one of the following conditions exist (here is the bad part):
1. The male plug and female locking bolt threads are frozen (rusted) shut, in which case the key can be turned outward while the locking bolt will remain stationary and not rotate (remember, the male "plug" thread is forged with the bow and does not rotate; or
2. The key threads and/or locking bolt threads are stripped, in which case the key is unceremoniously removed from the locking bolt.
In either case, the likelihood of being able to open this cuff, even with an original key, is not very good for the reasons I have stated.
Here are a few observations in support of my hypothesis:
A. Inspection of photos 8 & 9 reveal that the left cuff has been attempted to be pried open, as evidenced by the non-parallel mating surfaces between the movable and fixed bows. Perhaps someone was unable to open the cuffs (beyond 1/16 inch) using the key and then took to prying with a screwdriver or crowbar. Anyone who has tried to remove a rusted nut from a bolt (e.g., exhaust manifold) knows that with liquid wrench a frozen nut can sometimes be turned a little before stripping the hex head or breaking the bolt (!)
B. Inspection of photos 1 & 3 reveal that the movable bow on the left cuff is bent inward, perhaps in an attempt to dislodge the bow outward thereby releasing it from the lock. Of course, this is futile, as the plug threads are very strong and the cuff would likely break before stripping these threads.
C. Inspection of photo 2 reveals impact marks suggesting that someone has pounded on the ends of both of the fixed (rounded) bows, perhaps in an attempt to free the frozen lockwork.
D. Inspection of photos 5 & 7 reveal that the lockcase cover on the left cuff (photo 7) has possibly been removed in an attempt to free the bow from the lockwork. Of course, if the threads between the male plug and female locking bolt are rusted together, then removing the lockcase may be futile since the locking bolt cannot be removed unless it is free from the plug and not much more additional torque can be applied to the bolt when it is captured inside of the lockcase.
On the other hand, it is possible that one or both cuffs may be able to be opened with the correct key, but given the very limited amount of torque available (remember, only the friction of the key and bolt ends pressing together provides the force to turn the locking bolt), I would not count on being able to do so since a previous owner has apparently already tried and the left cuff is now in a partially opened condition.
Since this is an information forum, I have provided information that I know to be correct (the cuffs are genuine, and how the lockwork functions) and information I believe to be likely (at least one, and perhaps both cuffs may not be able to be opened) based on speculation of the physical condition of the cuffs from the photos shown. So those bidders who do not care whether the cuffs will be able to operate (or believe in spite of it that they will be able to open the locks) can ignore this post, and those who do care may choose to weigh the information above when bidding. After all, these cuffs are still worth a lot as wall hangers, which is what they were previously.
P.S. For those that have never owned or handled one of these cuffs before, the "swivel link" does not swivel like a Rankin but in fact is a solid link.