If it was a brooch, the area for the pin would be towards the top of the object in question.
That’s not necessary at all. It’s in the center and the main portion provides plenty of support both up and down.
Not necessarly ... a broach ... could be attached to a shash type (leather or webbed) belt. Does not have to be a pin. Looks like something snapped into the the holder at the top. The curved piece is the clasping part, gives just slightly.