I bought this on eBay only because it had the original Sahara logo on it. However I have no idea what it is and neither did the seller.

It measures 1 3/8" in diameter and total depth is 5/16".

Solid metal, brass I assume. The medallion pivots off of the top rivet which connects the 2 pieces.

Reply inline with your guess. Best guess gets an obsolete chip sent to him/her