Featured Sandcast NA Silver Buckle; Anyone Recognize The Pattern, or Maker?

I uncovered some of my silver hoard...there'll be more of this stuff.
This buckle is ~3 3/8" long, ~2 3/8 wide, ~1/8" thick; weight is ~70 grams. There isn't an identifying mark to be found on it. Google image search found no good match for the pattern, tho' several have somewhat similar design elements. My assumption of NA could be erroneous; it may be Mexican, I suppose. It's as-found locally, about 25 years ago, in a real ratty junque shop on Hood Canal. I haven't polished it, yet.
What say y'all? Thanks for lookin'!

 

Can't help with identification or origin, but I will say that I wouldn't polish it. I think the patina on a piece like this indicates age and, if you're going to sell it, not-polished does much better around here than polished.

 

Y'know, that's good counsel Potts...Thanks!

 

Hard to tell from photos but it looks like some kind of mark

 

Sand cast Navajo silver buckle. Could be anywhere from 1940s to 1970s as a wild guess.

 

I've heard of tufa casting, but have no clue about its appearance, or other hint about spotting such inna wild.