Bias ply tires take a set (a flat spot) if they have been doing anything but laying flat since the last time they were hot. Even brand new tires can be stored wrong to cause an out of round condition. Front runners are Bias Ply. before you balance or try to true them you should do something to get them hot and rotating. Driving is the best.
Heating in the sun and spinning fast while up on jacks might work. And then balancing shouldbe done while still warm before they cool. I'd bet that shaving isn't necessary to correct out of round rubber. I'd also bet they were round and even when made and siting on the thread has deformed them.