Blanchard always used a letter set to mark the inside of the heels of his spurs so anything that is engraved or carved is a fake, of which some have been documented. They are typically marked “E.F. Blanchard”, a style number 2,3,4,5,6, or 8, “PS” “SS” or “TS” for plain steel, stainless steel, or tempered steel, and usually also with the name of the place he was working at the time which include:
SAN ANTONIO N.MEX.
SAN ANTONIO N.M.
Most of the spurs that I see are from Yucca, where he did most of his work.