It's from the right era but I don't think it's a Chevrolet specific filter.

There are a few of pancake filters identical to yours for sale on ebay right now for $75 -$200. None of them are specifically listed as being for Chevrolet. Engine pictures of '39 Chevy trucks don't have that filter that I can find.

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)