If that's all the PPI came up with then I personally would go with that - depends of course the asking price.
Yes, I also have very small leak emanating from the cam covers since I've had this C4 (10 years), but it's pretty negligible. Tends to gravitate to the bottom engine crankcase when the engine is hot and in my case only 1 or 2 drops onto my drip tray. Very acceptable. Might get round to replacing the gaskets, which can be done in situ, but don't see the need for now.
Had too a rear main seal leak when I bought the C4, and as I was having an RS clutch and flywheel swap out I got this done at the same time. Point this out to the seller and then get a second (independent) look and get it priced up along with a new clutch (very dependent what year model this C4 is) - better still price up an RS clutch and flywheel replacement as the small additional cost (few hundred extra) makes it worth it. Another look at the seal leak may say run around with it as is with view to to get it done as a winter downtime job.
Hopefully you have a contingency budget on top of your buying cost to iron out some small creases and a few fixes. If I can help with any questions just post up here or PM me any time (or even go and check out renlist). Good luck and use it hard!
Marcus