I just read an article re. The Filling Station and their research on the correct color for the various years. If you insist on factory correct check with them. Or you could shop around for a light to medium grey ? Chassis black is sold by lots of paint brands under various names like simi gloss, flat black etc. You could check with a local auto paint store.
Best of luck


It's easier to get forgiveness than permission!
1946 1/2-Ton Chevy
1953 Chevy 3/4-ton Factory Stakebed