Bama,
If it's working and nothing wrong then that is an excellent price. If you don't buy it, depending on how far away it is, I certainly would consider it.
Changing fluid and filters is no biggie, I would not take anyone's word as to what they did or did not do to it. IMHO - I would change, check and adjust everything mentioned just to be on the safe side.
Where are you located? The price of tractors are greatly affected by how far it's shipped from the port of entry and as mentioned how well it was put together and serviced. Shipping costs are also a factor in the ultimate final price of a tractor. A tractor close to a port would generally be lower cost than one shipped to the heart land.
The reverse gear speed in High range - HaHaHa yea that's got my name written all over it. It's my pet peeve of the 300 series Jinma's. I have a 354 but have learned to use low range, if you ever want a white knuckle ride, just shift to high range, put it in reverse, rev the engine, slip the clutch, then rocket sled back-wards into the barn or through the other side
Oh and that 304 can be turned into a 354 by backing out the throttle stop on the injector to get 300 more RPM's. A 354 is a 304 that's set to top out at 2300 RPM's instead of 2000 RPM's. A 304 is a de-tuned 354. (IMHO)
Oh and you will probably have to perform the t-stat fix to get the engine up to operating temperature. Here is the link to that -
T-stat FIX
Larry