Hi Toby and Bill,
If I were the buyer of that painted Airstream I would consider the value
lower. Vintage Airstreams are polished aircraft aluminum, Argosys are
painted. I once saw a hale damaged airstream painted with textured white
paint...didn't have the same value, so the dealer was willing to let it go
at less than market value.
The fact that Wally painted the roof is integrated in the original intrinsic
value however paint applied after manufacture is an alteration of the
original product.
I like the science though. I think the painted surface would absorb less
than the polished aluminum. The next time I see a painted Airsteam I'm
going over to get a reflected light reading with my Luna Pro light meter
then compare it to my polished Globe Trotter.
Just my two cents....GAS