If I may be so bold, let me give you some of the best modeling advice you're ever going to get: do NOT get hung up on "correct colors"--especially when it comes to "old photos".
First of all, there's the disparity between individual mixes of paint from different manufacturers and wartime expediencies. Next, you have the effects of weather, fading, shadow, angle, etc. Add to that the peculiarities and quirks of actual film, and how THAT changes color over time--and then there are both the calibration of your computer monitor and/or of printing processes.
Realize that NO ONE can say with any definite accuracy of EXACTLY how dark, light, or tinted one color is vs the next, and that there really IS "NO" "correct" colors. In truth, we all have our own opinions as to what the "correct" color shade or tint is, but no one really "knows".
If the shade seems too dark for you, lighten it until it makes you happy. Modeling IS "Art" after all!