Here is the 12v version on Standard's online catalog. It doesn't explicitly say 12v but everything that's 6v is labeled as such.
https://www.standardbrand.com/en/ecatalog?part=HS572%20-%20A%2fC%20%26%20Heater%20Blower%20Motor%20Switch&type=p
1950 Chevrolet 3100 (Ol' Roy)
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
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