Modern fuel isn't the same as fuel from 50 years ago. The spark plugs will be tan or light grey when burning normally. Go pull one from your modern daily driver and look.

The old spark plug charts we used to use to diagnose problems aren't really useful these days.

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)