This is the correct split two piece rear deck for all 76mm shermans.
Look very close at this tank travel lock and wherre the hinges are mounted.
also, paint is in the eye of the beholder, and I have used stock bottle paints of OD that I did not like. Testors, and tamiya. Your tank was new to the European theater so it should be fresh paint, which is dark OD to be correct, not green and not brown, but so close it can appear to be either in various light. Alot of mumbo jumbo about tank green is thrown around about fading etc, but not on a 76mm, no time for it to fade in WWII.
I just finished tons of experimenting and have what looks perfect to my eyes as a real military vehicle restorer.
Using tamya bottle paints, 5 parts black 3 yellow and 1 brown makes an awesome dark OD. Then spray clear gloss over since by mid war tanks were semi gloss, and the color becomes perfect.