Depends on how it has been cared for really.
Definitely worth checking for and treating any corrosion at the bottom of the main frame member just around where the main stand pivots. Also worth checking the oil pump and it's cable for correct operation, and the crankcase seals (Gearbox oil will smell of petrol, and / or you will get lots and lots of white smoke in the exhaust).
If the original mechanical voltage regulator and metal plug cap are still there, I would replace them ASAP.
Otherwise, it's just the normal checks you would do any any used bike ie. brakes, bearings, plug, points and timing, forks and seals, electrical connections and loose fasteners etc etc.
Simples