Yeah brother. An adjustable block isn't a thing you have to have. But running an extended amount of time suppressed, it does make it a little less harsh. Less gas being blown back into your face and such. 5.56 guns.....you don't really need an adjustable block at all. 300 blacks don't really need them either. 7.62's on the other hand. If you're gonna spend some time behind the trigger with em, it'll definitely make it a more enjoyable time.
I've run my 10 SBR (no adjustable block), and it runs just fine. But not for a long time though. The gas will start choking your ass after a while if you're ripping through enough rounds.