The one thing you will want to check is the condition of the recoil buffer. It is a small nylon insert that cushions the blow of the recoiling slide against the frame. They tend to break down after time and need replacement. Numrich used to have them, but I am not sure if they are still available now.
The other thing to look for is a cracked or chipped feed ramp.
Edit: I just checked their website and they are still available: