This clip is stamped with artist’s logo on the reverse along with incised “© 1976” and “STERLING”. The Hart attribution is supported by the same die stamp “STERLING” and date numbers, which are nearly identical to a signed with initials belt buckle by Jim Hart.
The style of the image and the materials cement the attribution. In very good original condition having light scratching from being carried in a pocket . Among Hart’s earliest works. See image below for comparison of markings on a Hart signed belt buckle.