The only "dumb" questions are the ones we don't ask.
Some bolt carriers (especially some 9mm) will hit that stupid block preventing the cycle from completing.
To be sure the CMMG is not one of them, you'll need to call CMMG. I'm thinking you may be able to
get away with it, but it's best to get the straight skinny fromm CMMG.
I would also be concerned with your FCG, especially the springs, should you be forced to replace the Colt
FCG because of light strike issues. The Colt "block" may limit your choices if you need to swap FCG's.
That block may be of the pinned type and you could mess up your lower if you monkey with it. Newer lowers
I've seen have the block feature integrally machined into the lower and requires machine shop skills to deal
with it if removal is desired.
The block is there to keep The Left's imaginary domestic terrorists from going full auto, if you want full
auto in your .22 you'll need another lower. Remember Colt lived in the Liberal Peoples' Democratic Republic
of Connecticut and was always being used as a punching bag by the Lefties. So they put that block in there
as a pre-emptive strike against the anti-gunners. It sucks!
Call CMMG. Good luck,