Because there are many manufactures of wheels for the same size tires and Hi Lo may have used different wheels for the same model trailer, you should get the part numbers off of the bearings and seals.
If I was to buy them at Napa they would be a BR2 and a BR4, I work at a place that sells trailer parts so I just grabbed 4 of whatever I had for 3500 lb axles. What a mess LOL