WM on antique gold chain holding a jade pendant

by Toni Shiurba
(Friday Harbor Wa. USA)

I inherited a 12 inch long light green flecked with a few darker green areas, scalloped in the shape of a flower approximately 1.5" in diameter jade pendant and 3 small green jade beads with 6 orange small beads.

The gold chain is marked with 1/20 12Kt and the letters Wm on the flat identifier of the chain and 1/20 12Kt GF on the round clasp. I know the meaning of the 1/20 12Kt describes the portion of gold content and am wondering what the WM stands for.
Is it a known maker of jade necklaces long ago? The necklace is over a 100 years old. I've attached a photo. Thank you.
Toni