Will a gasket change fix the problem for a long time

I am going to buy a $6,000.00 used car and in the inspection, they told me that there is an oil seep in the gasket and the gasket needs to be changed. They told me that the problem is minor and that the change is about #300.00.
The car has been owned by an old lady in the last four years who has driven about 3,500 miles per year. I think based on the receipts of the maintenance. She has changed the oil twice in his period which seems okay in terms of mileage but I think not in terms of how long the oil remained in the car.
My question is, if I get this gasket change done, will there be no other problems in the long term or there is a possibility that the problem will reappear or there is a high risk of an engine fail? This is going to be my first car and I am a newbie in the car world, so any advice is highly appreciated.