I mod a few communities and haven't seen anything relating to comments pending mod approval. The only related setting I have on the communities is to restrict posting to moderators (comments on the posts should still be open to anyone).
It's pretty easy to see on r/askeconomics. All top-level comments there require mod approval, but will add to the number of comments while waiting for approval. So it's pretty common to see posts with 10+ comments listed, but nothing besides the pinned automod comment is visible.