They are a great tractor.
Built like a tank.
Make sure Owner has not used ether to start in winter as this really screws up the cylinders and rings.
Bought mine from a farmer 5 years ago,
Started it up, did not smoke, all the hydraulics worked, mine had a front end loader on it also, bought it and brought it home
Look to see if it has leaks especially from PTO shaft at back. a bit of seepage is normal.
In a nutshell a great tractor, Have had mine for 5 years now, it is a 1962 FSM, and absolutely love it, use it for clearing snow in the winter.