Thanks again (and again) guys,
I just spoke with the seller, as well as the mechanic that is doing the annual. The seller is a straight up guy (as previously mentioned) and has cordially invited me to not only test fly the airplane, but even take it away (for up to 5 days if needed) and have my mechanic look at it. Apparently he feels comfortable with me, as well.
The sellers' mechanic feels the 'crease' has been there a long time and doesn't think it's a concern at all. So, I am going to drive to the airport tomorrow, meet with the mechanic, inspect it carefully, pull the seats and the inspection covers and look inside with a scanning electron microscope (!) and make a decision. If I decide the fuselage crease is acceptable, then I will go the next step and arrange a pre-buy inspection.
Thanks to all that have given input. It has really helped.
Charlie Rowlett