It is only risky if;
1) You know nothing about the equipment you are buying
2) You have no one to check it out for you before you pay for the unit
3) You believe the dealer
4) YOU BELIEVE THE DEALER.
You need to have a thorough predelivery inspection done by someone who knows RV's and is not associated with the dealership.
Your purchase will be "as is" regardless of what the salesman says about taking care of you, the contract is the binding agreement and it most likely will say "as is".
During the predelivery BEFORE YOU PAY all (REPEAT ALL) systems are proven to function. THE refrigerator is a very expensive item and can take 24 hours on initial cool down. One gambit by a dealer would be to say "Oh we forgot to plug in the rig in yesterday that is why the fridge is not cool. You sign, fridge does not work, you buy new fridge. SO everything must be proven to work no matter what.
The tires might look like new and the tread may be great but if the tires are 7-8 years old they have aged out (sitting and sun deteriorates them worse than auto tires cause they are not used much). DO NOT BELIEVE the dealer look for a date code on the inside of all tires. If they are ST tires they may be inferior for the job they must do and some here have gone to LT tires to avoid blowouts.
Hidden damage from water leaks could be an issue and you or someone you trust needs to get on the roof and look at the roof. Is it well maintained? Does it need caulking?
Interior of all cabinets and closets needs to be inspected for water incursion.
Frame needs to be inspected for damage as some Lippert frames seem to be having issues.
How are the trailer brakes? they need to be checked for function
Lastly what do you have to pull it with. That rig can dry weight out at up to 8000 pounds depending on model. The salesmans assurance is not enough. You need to figure out the weight from your tow vehicles placard. If you post the model of the trailer and the make and model of vehicle along with the ratings off the placard on the tow vehicle people here will tell you if oyu have enough vehicle to SAFELY pull the trailer.
There is lots more but these are the basics on buying ANY used RV>
REMEMBER the salesman is not your friend. You are the way he feeds his family and the kids are hungry.
Traveling with my best friend my wife!