Less than 130 on new engine, he blew the engine up at 400 hours. Total hours of tractor is 530 now sir
You have mentioned all of the keywords that I would be looking for in a used tractor. Dealer serviced when there is a problem, shedded, FEL, box blade, shredder. Seldom used (low hours). GST. Great price.
Years ago, I purchased my 2002 L3710 GST from a dealer 2 states away, sight unseen but delivered by a third party. Sounds like what you are looking at may be the older version of what what I own. I absolutely love the tractor and it's GST. I had a Kubota HST once but sold it when it had 200 hours. GST is quiet (HST isn't), GST is fuel and power efficient (HST isn't).
If you haven't noticed, there is a lack of good used tractors at a good price these days, especially a tractor without the emission stuff. Between manufacturer's pulling back production in 2020, forcing new owners to buy used, to free government cash, the used market is HOT. You are looking at a great price.
The only thing I would do in your situation is to be sure to test functionality as much as you reasonably can. Test all gears for operation and noise. Look for leaks - these tractors are known to have leaky front knuckle seals, so don't be turned off if you see it. Make sure electrical items work and all dash lights are on when key turned but engine not started. Test both back brakes independently. I once bought a tractor from a guy who used the left brake for parking but forgot to release the brake when he used it, so that brake was almost completely worn out after 150 hours. If you are not comfortable with all of this testing, pay an experienced tractor owner to check it out. I would not use a dealer, for I have witnessed them missing major things because they have no 'skin in the game'. Most of all, consider the seller. If you think he is out to hide something or dump a problem, walk away. However since he got the engine fixed by the dealer, I highly doubt there is anything but the lowest amount of risk.
Finally, make a decision asap. It could easily be sold in a day's time if he advertises it.