From the same estate as the buermann spurs that I have listed. Buckle is As-Found, I have not cleaned or polished it.

Buckle measures approx 3 7/16" x 2 3/16" and will fit a belt billet up to 1 1/2". weight is 53g

Buckle is stamped HAND ENGRAVED STERLING. I don't know who the maker is but I'd bet the engine/machined turned back is probably the clue.