ID help on necklace/ brooch

[saorsa54]

Thanks for taking time to read my post.

I picked up this unusual necklace in a thriftshop recently, other than I "think" it's Mexican silverI know nothing about it. It looks like a calendar of some sort, with it's focal being a sun; on the bottom edge just above ridge are the letters REY . My digital isn't made for upclose so my pictures aren't the best..

It appears to be # 23 in the eagle, Which is upside down compared to other marks and above sterling I cannot make out the signature, looks to my bad eyes like _ _ _ DENMER.
Pic

Pic


Any help is appreciated
Kathleen
saorsa54