Info on Found Shakles

I'm a collector but not of handcuffs and I know where to go to find out info when I need it and that is to another collector. I found your site through Google and have a question for all of you concerning shackles. I found these at a sale and purchased them from a lock collector. These were in a lock collection that he purchased. He had to buy all or nothing and he collects strictly large locks dating from 1900 back. He didn't consider these in his field. He said these were from the Civil War and used at Fort Delaware where Confederate prisoners were held. He did not know much else about them. Can someone please help me with identifying these. Could they be Civil War era or slave shackles? I have read several topics here in your site and see pictures or a set that looks like these that is said to be from the 16th century or before. I know nothing about cuffs or shackles but am extremely interested. They are for sale at a reasonable price if anyone is interested or if not they will go to Ebay. Thank you for your courtesy and interest.....Bud Davis