Signed&stamped 925 vintage Mexico sterling silver Mayan calendar pin or pendant

Signed&stamped handcrafted vintage Mexico sterling silver Mayan calendar pin or pendant. the artisans name, 'Hechoen' is signed on the back, with the word 'MEXICO' below. Beneath that is stamped 925 RDC. Slightly below all the insignias is a picture of a weight or a lock with the number 1 in it. I would guess that is either a makers mark or a way to track the sales of this piece of art and history.