I don't have a reference in front of me so pulling this outta my hat from what I recall reading and am happy to be corrected:
I think "work" vests that were not made to be part of a suit might well have been made of one type cloth or, self backed, as its called.
Men coverd their shirts, with overshirts or vests so likely vests were common of all descriptions and types. Toss in how many were hand sewn and I doubt you got what you wanted as much as what was available, so if you had one bolt of cloth . . .
Remember, vests were also called waistcoats and were worn stand alone, or under not a suit coat, but rather, a heavier overcoat when outdoors, for some time. This is why so many waistcoats/vests were of differing material/pattern. Matching suits, or ditto suits, were less common earlier, more so later (especially since one of the garments--trouser, coat, vest--might wear out before the others so mismatched outfits were common).
If the backing wore out or was torn it could easily be replaced as well.
I am betting just about any vest, coat, etc. combo as long as the cut and material is accurate would fit right in to the old west.