I read on howtobuyvintagejewelry.com that he made silver overlay on copper jewelry but when a question was asked about a solid layered copper bracelet with chip inlay roadrunner and cactus, the responder waffled and recommended several appraisal sources instead of giving an answer. To me it seems plausible, especially when starting out in the business. I would compare the stampings and inlay against his known pieces. Best of luck on your search.
@saef did a discussion “Talking about chip inlay…” on chip inlay in 2017 under Real v. Fake: (Talking about chip inlay: If you're thinking of buying a piece)