You can throw the better B-bolt from an XO1 on your GX, they're readily available and just pop right in. The GX is metal-on-metal so wears the derailleur body against the bolt as we hit 10 million little bumps out riding. Just don't wait too long to do it!
Now it would be darn nice of SRAM to just include a B-bolt with proper bushing on GX. Maybe they've improved this on the current GX derailleurs? I heard they made some updates, just not sure what.