Nice score. When you refill the oil I recommend having an attachment connected or at least a securely mounted block-off plate on the front. Otherwise, if it tips forward you will have a big oil mess on the floor.
IIRC there was a QH plow blade. Not positive. But if they had one of those, there would have been no load on that needle bearing, so hard to see why it would come apart.
Regardless, those old needles have got to go. It's possible that some of them have slipped down into the bottom of the case. It's not unlikely that they've been sitting there for years without causing trouble, but . . . .