The Versys is a very durable machine. Many members here have a lot of miles on their Versys. The engine has a reputation for longevity.
27k miles should not be a problem at all for the engine and transmission, assuming the owner properly maintained it and didn't beat the hell out of it.
At 10+ years old you will have normal age issues. Anything rubber may need to be replaced. So, a lot of hoses and seals related to fuel, brakes, and cooling. Fork seals maybe.
My advice is to have the bike thoroughly evaluated by a good mechanic. It may cost some money, but better to find out ahead of time that there is an engine compression problem or the forks need to be rebuilt.