Darby Crown stamp?

I am making keys to a Backstrap darby 104. The cuffs are stamped with 'warranted wrought' in an approx 1mm high font. Beyond that toward the hinge is what appears to be a crown and possibly another word but its small and faint. The question is, has anyone seen a Crown stamp on a darby?  Updated image of what is visible.

I never have but I have seen such markings on bayonets I believe. It could symbolise it was government use. If you could post as high res images as possible of the actual cuffs it may help remind people or maybe someone will be able to figure out the feint text either by photo-enhancement or it's font and placement indicating to someone what it might be, based on one they have.

That crown shape would be a queen's crown. King's crown tends to be more smoothly dome shaped on top compared to the Queen's that has a wavy shape with a bit sticking up in the middle.