Are there any numbers stamped on the back other than patent numbers?
Maybe one of our members has an old Hoyt catalog or maybe look it up in an old Shooter's Bible.
I've got a couple of similar Hoyt holsters, I believe yours is for a 6" or longer barrel revolver. Does the maker's stamp specify Oregon as the company location?
They're pretty neat old rigs. Not sure if that Hoyt company was related to the Hoyt holster outfit in later years located in southern California.