The 251/22 didn't enter service until around Dec 44, so it wouldn't have been seen on the Russian steppe. Persoanlly, if you want historical accuracy, i wouldn't put these two together. It may have been possable if there was a Vorpanzer taken from a training unit and used in a last ditch battle somehwere. As for colours, the Vorpanzer would be gray, the /22 would be camo.