If I understand correctly you're talking about getting new bands onto an M44, possibly by removing the bayo mount?
Looking at mine, I can't really see a safe way to put bands on if the old set are missing... The safest (or least expensive if a mistake is made) in my mind is to bend the bands open enough to pass over the barrel and then bend them back. Hopefully it wouldn't damage them too much, but if it does, at least it doesn't cost you the whole assembly and all the bluing getting messed up.