Hi gang, I dive an old (approx. 15-20 years old) Oceanic reg which as far as I can tell is an Omega or at least Omega style. The second stage is red and it looks like a little shower head. I'm thinking about doing the nitrox cert and it occurred to me that a reg that old may not be happy with the extra O2. The reg has been shop serviced regularly. Can anyone confirm/deny the nitroxability of old regs like this? Many thanks.