yes if he can hold his head up. my son has been holding his head up since 2 months and has been sleeping on his stomach since then he’s 5 months now
My son stonach slept since he was 4 months. I always start him on his back tho.
I think they say long as they can turn their head on their own at that point that it’s fine. Plus if he’s on you you’re more bound to notice if something is wrong. But if he’s uncomfortable or can’t breathe in that position he’d turn and move his head as long as he’s got that neck control.