As a general rule, if you are not absolutely sure that the previous owner has changed the oil, do it now. The first oil change on a chinese engine is critical as they do their "finish machining" on the moving parts during break in, much like 1950s engines. that tractor is marketed as having a synchro shuttle trans and if it does it means you can shift form forward to reverse and back without coming to a complete stop (stopping will increase clutch life however). Go around and tighten every nut and bolt you can find, if you find a loose one, it is often a good idea to put in some blue locktite and retighten. Keep the radiator clean. keep a close eye on condition of rubber parts.
There are a few Lenar dealers around that should be able to provide parts support. sounds like you got a good buy.