Definitely a 735. The T bar on the RH handlebar in front of the throttle. It's broken, of course. Did he still have the engine and clutch? Did you make him an offer?
It has brakes and a differential lever on the right handle bar. Those, along with the splined PTO fit the 735 features.
(ooops, just saw this was already determined)
Ran it without any oil? Ouch. That tells you anything you wanted to know about maintenance and care. Pass.