Despite the damage, this set of handcuffs sold for $68.09 (Plus $10.50 shipping).
Handcuffs marked H&R Arms Company, Worcester Mass pat 1984677 ... made in USA ... with key .
These were made by Harrington and Richardson Arms Company, the maker of firearms - revolvers, pistols, shotguns, rifles - and the patent was issued in 1934
These work fine, and include the key. The key inserts vertically into the cuff, see the photo.
There are two padlocks attached. The small lock re-connects the chain where it was once separated. The large lock is used to shorten the connection and may be cut off (by the winner).
The cuffs show their age, there is wear and freckling on the plating. - eBay