You most likely do not need new wheel bearings, just a good cleaning and repacking should do it. However if you need new ones, should not be difficult to match up at a local NAPA dealer.
If its been sitting for 30 years, it probably has its original split rim wheels which should be replaced.
Many of us, including me have replaced our old vintage axles/wheels etc to be on the safe side as well as giving us all new running gear.
Welcome to the forums!
1956 Flying Cloud
Four Corners Unit
Albuquerque National Balloon Fiesta
Vintage Trailer Academy - Formerly the original