Quoted:
I don't see any issue as long as the barrel is under 8 inches and the manufactured weight is under 50 oz. unloaded. As always you're on your own and YMMV.
What does "8 inches" have to do with any pistol?
Being he is adding after market parts,I would think that "manufactured weight" doesn't apply,as he is not manufacturing the gun.
Your good to go with your mods on a Glock.
(c) a semiautomatic pistol that has an ability to accept a detachable
magazine and has at least two of the following characteristics:
(i) an ammunition magazine that attaches to the pistol outside of the
pistol grip;
(ii) a threaded barrel capable of accepting a barrel extender, flash
suppressor, forward handgrip, or silencer;
(iii) a shroud that is attached to, or partially or completely
encircles, the barrel and that permits the shooter to hold the firearm
with the nontrigger hand without being burned;
(iv) a manufactured weight of fifty ounces or more when the pistol is
unloaded;