I wouldn't be overly concerned. The hours are low but, it has been used briefly.
Maybe offer to pay for the gas, then start the generator and run the A/C and other 120 volt appliances for an hour or two. If there's no problem, I'd say you're good to go. If nothing else, it will make you feel better and, you'll know the generator is working properly.
I would definitely change the oil/filter and fuel filter if you make the purchase. Or, better yet, have the seller do it or, adjust the price. No harm in asking.
Let us know if you purchase the Fiesta.