My view, which you might suggest to him, is that a unit rechecked by the factory is even more likely to be trouble-free than a brand-new one.
My brother-in-law wasn't quite that lucky. He got sent a bad unit. It had a bad rear channel. If you do go this route make certain you keep all the original packing.
He got a full refill minus the cost of packaging as he didn't keep the original box.
It took two weeks to get a new unit sent to him.
Rick
"A fear of weapons is a sign of retarded sexual and emotional maturity." Sigmund Freud