early 1949 pickup vs late 1949 pickup which?

[wanutsared]

I bought what the guy said was a 1948 Chevy pickup. Your site explained that the gas tank was moved inside the cab in 1949. I think I have a replacement hood, serial # gone on door. Changed out engine, so no serial # there. The hood says "Chevrolet" in front & on side, so I know it's a 1949, the gas tank is inside, and the shift is on the column.

How can I tell if it is an early vs a late 1949 if the hood has been replaced? ??