53&me, for replacement panels a good place to ask is in the paint and body forum..........however, JimCarter has been Stovebolt friendly for years and Classic Parts has been pretty good to............however, being in Utah I'd check the shipping rates. My postal guy tells me as long as I ship East I'm ok but going west is a different story????? So you may want to check in with the Filling Station or Chevs of the 40's. I find those two a bit pricey but do what you have to do.
There are others that sell them so shop around.....most all of them come from only one or two makers.
.....Since your in Utah you may want to check on Brad Allen. He knows LOTS about these old trucks and lives in
SLC........ and I have a sister in law, nephews and nieces that live in Provo, Orem and Mt. Pleasant.