Yes, I think earlier models. I'd run across them from time to time when doing my daily machine overhaul/rebuild at work.
Not too rare, but fairly uncommon....
There was a retrofit/addition someone came up with once, that was a small adjustable valve that you could drill and tap onto the outlet hole, that allowed you to adjust how quickly the air came out. Allowed for additional cushioning for wear and tear on the mechanical parts during handle pull and reel kickoff. The device didn't get a lot of notice. Didn't seem to do a lot, but some mechanic somewhere made the thing and manufactured limited amounts I am guessing. I do think a working rubber seal allows for longevity with wear problems, but then these machines aren't being played 24/7 anymore, so that's not much of a factor nowadays.