Those tires are not for a bolens and he means the Z in the center of the model and serial number.
Interesting, I did not see that 'z' thanks for clearing that up. So, those little tires are interesting I'll hang onto them for now. I took a close look at a spot that was never painted over. The paint is not metallic so not sure just what color it matches up to. The Engine is as follows:
I'm guessing that the engine is a 1956? Thus the tractor is no older than 1956, just a guess?