Purchase question regarding S500

Guys,
I'm in the market searching for a 92 to 96 S500. After reading numerious posts in this forum regarding the A/C problems with these models and it's expensive repair especially with the evaporators etc... I"m curious.. is there a way that I can find out whether or not the previous owner had already done the repairs on the A/C system or not. Just by viusal inspections ? This way I'd rather go with a high mileage car that has the repairs already done rather than a low mileage one that I'll have to end up spending money on the A/C issue that is known to occur at some point in the car's life.
Any input would be appreciated...