Welcome to the forum. It sounds like you have found a nice machine. Many owners don’t put many hours on their tractors it is not uncommon to have 270 hours after 7 years. Are you buying from a dealer or private? As you comment it is important to check that everything works as it should and to check for leaks. Does the tractor come with an operators manual? Make sure to get one as it will cover maintenance.
My recommendation would be to do a full service on the tractor, so you have a benchmark for future maintenance. I recommend that you replace engine oil and filter, hydraulic oil and 2 filters, air filter, change fluid in front axle, grease everything and check all pedal linkages are adjusted correct. All covered in detail in the operators manual.
A mx5100D is a manual gearbox, if yours is HST, it will be a MX 5100 HST.
Good luck with your new tractor,