A 1/2 HP should pull 5 amps, and a 3/4 pulls 6.8. Must be a 1/2 HP. They don't make pumps like that anymore. I think you are probably just as likely to have a problem in the winter with a new pump as you are with the old one. If it were me, I wouldn't touch it. I have one that is 28 years old, and I trust it more than a couple of newer pumps I have.
The o-ring in the pitless will probably need replacing if you mess with it. They usually continue to work fine until you take them apart.
Unless the pump is stuck, that pipe should be fine.
32 years without a torque arrestor should tell you that you don't need one.
There has to be another check on the pump itself. Only a galv tank needs a check valve/schrader valve above ground.