Hey Staff Sergeant,
I've been working on 53's for a while now, and all the seats I've seen are OD green.
The old seats are big comfy canvas benches that are wide enough to seat about 4 guys. The benches can fold up to make room for cargo. There is a lapbelt for everybody.
The new style seats are one for each individual and they are not comfortable. They have a 5 point harness where they attach to a pendant in the middle.
But they're all OD Green, at least on the ones I've seen