I agree, lyric. I always thought red showed up as much darker in B&W photos, but that probably stems from my experience with early B&W copiers in the 70s, where red photocopied as black, and light blue literally washed away - remember those old light blue photocopy marking pencils?
Dan (GuppyJr) is another great 474th FG resource; hope he can jump in here. Another factor may be the fact that this was a hard fighting outfit on the ground going through Hell and High Water. Whatever command says about "official" colors might have less effect on a frontline outfit in daily contact with the enemy. Who knows, they might swap and trade airplanes between squads to even out losses or something, and may not always have time to paint the "official" colors onto the plane. Not sure.