The 'rated' shutter life on these cameras is just an average rate of failure. The shutter could wear out as early as 5000 clicks...or it could last 70,000. And either way, it's a serviceable part.
I'd be more concerned about the overall condition that the camera is in. How hard it was used and in what environmental conditions. I would think twice about buying a camera from a war photographer, someone who covered the Dakar Rally or a marine biologist etc. But most people do take fairly good care of these things.