The main volume of my old hybrids propane meter was pvc. Not only that, but I
solvent welded the gauge into it, and didn't use primer on any of the fittings

(the guage was made of some unknown black plastic)
There were no leaks, and the cold had no effect even though I may have gotten liquid propane in the meter once or twice. I was using 1/2" sch40 pvc.
In short, yes, it'll work, but I'd find a better way of attaching it to the chamber. Try a schrader valve+bicycle pump hookup. That way you can use the meter on more than just that gun.