You are correct, although the accepted story is that all bolts had to be removed from any rifles and were tossed in an oil drum for the trip home. Meanwhile, the G.I.s spent their shipboard time sanding and "prettying up" their rifles which resulted in a number of sick bay calls for a mysterious lung inflammation and the story that Jap rifle stocks were deliberately poisoned. They simply didn't realize the arsenal finish was made from urishi, a plant like poison sumac.
Meantime, the ship arrives stateside and the barrel of bolts is hauled out. Each man grabs a bolt and reinserts it into the rifle. Some of the bolts were tagged so the original owner got his original bolt back again. And that kiddies, is why you'll find a lot of Arisakas with bolt numbers that don't match the gun's serial number.