I was doing a build review of the Academy USSR M10. I was assuming the lower hull interior was all white, but from Steve Zaloga's M10/M36 book his interior illustration the floor and some raised structures were in grey. I was guessing that were unpainted steel plates but does anyone know? Thanks.

I'd say they were painted to protect the steel from the elements. As to what colour, I'm not sure. When I did their Achilles I painted the interior white, turret floor and turret interior in OD. That was based on what little reference I could find at the time and educated guesses.
I'm sure others might be able to give a definitive answer.

According to the Hunnicut Sherman book, the drivers compartment was painted white, while the fighting compartment and turret interior were OD.

Jesse

OD must be it, thanks a bunch!