They are pretty sturdily built, so you should be ok. Ask what HDD it has
(you'll probably use that until you get your SSD). Ask if it can write DVD's
- not very important, but it can serve you as a lever in price negotiation.
Ask about screen resolution - the screens vary a lot.
Once you meet the guy and the laptop - check for cracks in the case, make
sure the screen dimms as it should (sometimes the invertor breaks on CCFL
backlighted screens - make sure it dimms down uniformly). Look at the USB
ports, they sometimes get damaged. The inverter stuff is not a deal-breaker -
it can be changed pretty easily.
After you get it, get some thermal compound, a brush, isopropyl alcohol -
clean it, flash it, assemble it back, and enjoy :)