If it is like my NI, you can second source the bearing. HOWEVER... It won"t be a direct match. NAPA can get replacement bearing, but not that much cheaper. I went to an online bearing supplier out in Washington state,sorry, I don"t remember the name. Got them for about $4 each in lots of ten. Bolt and new nut will set you back about the same.
If I remember correctly bearing is 2" OD, and is mounted on a 3/4" shaft (bolt). You can replace with a standard bearing and a new bolt. You will need to make a shim out of a 2" washer, reaming out the center of the washer to clear the head of the bolt. The bearing is slightly narrower than the origional, thus the shim. Shim goes in cup first, followed by bearing with bolt inside, and finally, snapring and dirt shield. Once you get bolt through hole in star wheel, use an impact wrench to tighten nut.
You may have a major fight on your hands getting bolt back thru the hole in the star wheel - just doesn"t lign up nicely. Loosen bolts that hold star wheels, other bearing bolts, etc. I resorted to placing rake between two tractors, and using come-alongs to spread star wheels enough to get it in. There is tension in the basket, and I"m not sure why.