SMC in Diamond Mark Souvenir Spoon - Any Info?

[RArmstrong]

Does anyone have any information on this company? SMC inside Diamond mark on souvenir spoon. I have seen others online and everyone just says "SMC" with no information -- Mostly on souvenir spoons and some jewelry in both Sterling and Silverplate. All of the souvenir spoons I found online are American states and places so I believe it's a US company. I have exhausted all of my reference materials and sites -- so this is my last hope. Any help appreciated!

ps: I have also searched under "M" companies as the "S" & "C" could stand for "Silver Company"
My spoon (below) is for the state of Maine and is silver-plate.

[Traintime]

Likely, by Rainwater's similar drawing, Shepard Mfg. Co. Melrose Highlands, Mass. c. 1892/3-c.1923. Had a "specialty of souvenir spoons" among other objects.

[Traintime]

This sample would appear to be evolutionary between Rainwater's mark 2 and mark 4 (drawings) for this maker and should be considered an encyclopedic reference of a variant if her attribution is not in question.