The older 995 Classics and early models of the TS use bolts that are larger than the current TS models with the cam locks, so redrilling to a few millimeter sizes larger to let the older bolts through. It has been done before, but doesn't leave much metal for the recoils that result and I've heard of some cracking of the alloy as a result.It's been so long since I messed with an ATI stock, I wouldn't even know, but considering it runs the factory receiver cover you're going to need to make up the gap that is normally filled by the shroud. Plus you're losing the top rail for optics if you run without the shroud. You could cheat and get the old school style thrubolts.
Now. The next question is would MOM warranty this if one sent back the gun for repair? I know MOM has replaced with new when a lot worse has happened, such as a fire, but don't know about flagrant abuse such as drilling out a receiver hole.