Yes, the bottom is threadedDoes it have female threads in the back?
We Need a photo of the threaded side.Yes, the bottom is threaded
It is not a cufflinkIt could be some kind of a cuff link or pin if it has threads onthe back. It has a nice design
Could it be a button top… My wife has a pair of jeans where the main button looks almost identical to that. In fact she has a couple pairs where the main button and then the two on the back pockets are nicely done in a scroll work type of design. One of the buttons appears to be threaded on the top side and the other button appears to be riveted like much of what’s out there. Good luck with the ID!👍🏼