Seacrest green (not sea foam) was available thru 1952. In 1953, Ocean Green replaced it. Forester Green (the standard color) was used thru 1952, replaced in 1953 by Juniper Green as the standard color.
Info from
HERE. You can get samples from
HERE by clicking on the "C" just to the left of the small color chips. That will bring up a photo of a page of paint chips.
[on edit] Wait, we're talking GMC colors, which are different than Chevy colors. Try
HERE 1953 GMC trucks were available in 7 different greens. Or click
HERE and scroll down to 1953 to see the available greens.
Based on what I'm seeing, the only one of those 7 that's as light as your firewall is Neptune Green. Here's a sample from Jim Carter's website.