My Cricket gauge plastic cover came off by itself one time, I just push it back on with a snap.
I would think the gauge is similar to the FX and can be safely removed with a small chisel tool wrapped with tape to prevent any scuffing of any surface, just go around and pry up slowly.
Install the needle on loosely until you calibrate it to your gauge on your CF tank, after which reinstall the plastic cover.
You don't need to degass or remove the gauge off of the AT.
Wearing a full face shield wouldn't be a bad idea too.