Mexican Silver Jewelry - Mystery Mark

This Mexican Silver necklace and bracelet are similar but have different silver content 950 versus 925. Therefore, I assume they were assembled later by the donor to create a set. The necklace has a Taxco Mark on the back of the pendant, but a different mark on the clasp. From what I learned from my last two posts, I figure the necklace was made by a Taxco artist with a last name starting with "M" and is the 181 silversmith with that initial or is the 181 person on the tax roll. The mystery mark on the clasp is different from the mark on the pendant. Thus my question. Does it add additional information?
The last three pictures show the bracelet. The bracelet is 925 silver but has no artist mark. Any help will be appreciated.

 

nice !!!!

 

Thank you.

 

i bought stuff like this for my ex...mid 80's.

 

That’s sounds right for the stamp. I like it’s seeming simplicity but it is actually rather complex