If that should happen, one of two things comes to mind:
1. Hire an inspection service and direct them on what you would like to know about the car. Most will just look at whether the
oil is capped off, etc. so you need to be specific about what you need to know.
2. Present the problem to this forum and ask for help. Chances are someone on this forum is nearby and would be happy to at least give you an overall opinion. There are those on this forum who would be qualified to give you a thorough assessment. Don't hesitate to present the problem and see what happens. There is always that other forum for Factory Fives and many there would be happy to help as well and just as qualified. It's likely someone on here will know the car and the current owner...it is not uncommon for that to happen.
Good Luck