I agree with Doug on making sure rust isn't a big issue. Then again, $10k for a very nice looking and I'll assume perfectly running vintage sports car is not much to pay. I'm sure you could find one cheaper or maybe in better shape, but would you be happy with this?
Mine is a basket of problems holding over from 10+ years of poor storage. It's a 68 and there are some differences. The things that have required lots of time or money for me include: new radiator (does this run hot at all?), bad turn signal stalk (does it work well, feel solid?), rusty gas tank (not sure how you could check this without lots of effort), leaky P/S pump (check the P/S fluid resivoir for foam or bubbles), exhaust (how does it look? stock or stainless?). Check this site for other expensive and difficult problems to fix and study this car hard in those areas. A little rust here and there is basic body work. Lots of rust is catastrophic. I find the wacky mechanical problems that require very specialized knowlege and parts the real issue. Stuff like the fuel injection system. You're not going to be able to pop into the dealership and have someone help you there.
Bottome line, it's like they say about golf, don't aim for trouble. If you like the car, it will easily earn its cost back in great drives and jealous onlookers. If it sits in the shop or your garage, you'll kick yourself everytime you look at it.
Shawn Rock
Philly, PA USA
1968 280 SL 4 speed