The barrel is suppressor ready, but the inner diameter of the handguard is 1.3" so if you are trying to squeeze the suppressor under the handguard you will want to make sure it is thinner than that diameter.
I have been trying to figure this out as well. Where the uppers have a longer hand guard than barrel, I don’t think any 9mm cans will fit under the 1.3” rail. The only option I know of would be, if you want the 8.5” barreled upper you may have to buy the shorter rail just to swap. I’m not sure if they would swap it it prior to buying, with a 7” rail and an 8.5” barrel it would’ve good to go, as is however, doesn’t allow the room needed for a suppressor. Hope that made sense.
FM Barrel threads are 1/2"-36. Handguard will not fit any suppressor under it since they will be over 1.3" diameter You will need adapter or muzzle device to mount one, so NO, this is not suppressor ready.