Does the standard TRX use the same barrel nut as the TRX extreme? I have the extreme but would rather have the rails. If I order the standard is it just an easy swap by removing the bolts at the bottom, slipping off the rail, putting the otheer one on and retightening the bolts?
Yes. Easiest swap I've ever heard of.
The current production Standard and Extreme, as well as the VTAC, all use the same proprietary nut. I have taken a Standard off of one gun and installed the other two as a way to test this.
New production for at least the Extreme, and presumably therefore the other two as well, is going to a revised design whereby it attaches to the standard barrel nut.