Yes, RCV (Poly Performance) has sent out a replacement inner short shaft. No issue there. Working with Yukon on the outer shell for replacement. Already replaced the housing with another.
During the rebuild to install Grizzly locker and new gear set, I had JK sleeves installed as a bonus. The shop drilled the amount of recommended holes and plug welded them. Lost out on that effort. They had noted how thin wall the JK tubes were to the TJ/XJs and that they had to 'hammer' the sleeves into the tubes. JK's, they just push.
Upgrade is a possibility, but for now, cheaper to replace and keep wheeling. I questioned RCV about credit for the shafts, they would (didn't say how much), for another application set. Talked about Toyota (FJ60) and they have a set for, get ready, under 700! for them. I had (sold it) a FJ62 front axle (comparable to Dana 60). I'm looking for another now. 9.25" ring, matching 4.88 available, dual piston caliper, vented rotors (14" IIRC), 30 spline shafts. Even though stock application is pass side drop, its symmetrically mounted in the housing so flipping the housing over is no big deal other than to rotate the knuckles and redrill vent n drain. Or TraiGear, RuffStuff, etc have pass drop housing for plug n play.
Then any upgrade has collateral damage to include steering, brakes, links, suspension, ds, frame mounts, and that's just for the front. Do front got to do rear to match, then tires/wheels.