Yes CCI sells them "9475 Gauged Option" it Cost $33.50 and it includes a gage. I don't see much use for this, by the time you see a drop in pressure it is too late. But they do look cool.
Or if you get the vertical air kit it is a $15 upgrade.
As for the reg mod, you can not take out the V/A. but you can adjust velocity with the reg. Just adjust the bolt like mentioned earlier and then adjust the reg at the crony.