2000 Grand Caravan 3.3L Manifold Bolt Missing. Problem?

Just noticed after a mechanic swapped the old engine out for another that a front 'intake' manifold bolt is either missing or broken below flush. He didn't mention it nor did I see it until a week after the job was completed.

He does offer a warranty but was wondering how big a deal this is to be driving the vehicle with an intake manifold bolt missing? The motor runs great, so much better than the previous one which had bad compression and wouldn't idle.

Any input welcome.