GTX Admin - Are you after any particular scheme - e.g. red-outlined markings or otherwise? Given the JRB (C-45/Beechcraft Model 18) weren't exactly large, you could just about use any suitable era decals from another USMC platform. By way of example, the F4U Corsair was some 33 ft 4 in (10.1 m) long whilst the UC-45 was 34 ft 2 in (10.41 m) long.
Yes, you are quite right, and that's probably the route I will go. There would be a very small "JRB-3" or "JRB-4" designator on the fin, but at 1/72 scale, I can probably live without it.
At any rate, now I can't even find the JRB/C-45 kit I though would be so easy to find! I found one on E-Bay but got outbid. So, I am working on an alternative plan while I keep looking for that kit.
Thanks for the suggestions!