Assuming the Bearings are 32 years old, I think I'd replace them with a new set, and add the Bearing Buddy or similar system.
 Even if your lubing the bearings on a regular basis, that's a long time on the same set of bearings? Bearing failure is often sudden and depending on how well they were packed, they can suffer wear that you won't realize until it's too late :'(
 A few bucks spend now, will give you peace of mind for the rest of the old trailers re-birth.
 Losing a wheel and suffering a rollover with a couple of canoes or more plus other gear, your looking at thousands of dollars in damages/losses.
 New bearings/grease system will seem like a bargain then.