Originally Posted by Echoes-of-Honor
Can the air adapter on the back be removed to use co2 in the mags?
You can take the ASA back block off of a T9.1 if you like, but you don't need to to use 12g co2 cartridges in the magazines as your air source. You would only have to make sure the hollow co2 stem is installed in the regulator body. The OP didn't specify whether the standard hollow stem or the filled in dummy stem is currently installed, but new T9.1s come with both and he might have the other one in one of the little bags in the top of the photo. If not, spares can be bought at Tiberius Arms CO2 Stem - 81-2507 Tiberius Arms T9.1 CO2 Solid Stem - AC-4013
and you can see how to change them at Tiberius Arms T8.1 Pistol Solid Stem Install - YouTube
Even when using a remote line or the backblock ASA with the solid stem installed, you can still use c02 in your magazines for the extra push when you eject them. Although many people don't like the sound giving away the fact that they are reloading.
Good luck with your sale OP.