Really depends on how it was stored, and the bearing types. If it was stored in a damp environment, there’s a chance that the carbon brushes can fuse to the commutator. And if the motor has a sleeve style bearing, the oil-impregnated felt washers can run dry.
I popped the hood off; and the brushes were perfect. The bearings were a sealed type and the whole motor assembly turned smoothly by hand. So I tried switching it on. The motor runs well and there’s plenty of suction. sitting unused for all these years doesn’t seem to have bothered it none, which is great news for me.