Steven,
As an A&P it would be really hard for me to fill out a 337 on a repair that someone else made unless I could check it out in detail, much less get an AI to sign it off behind me. Depending on where this damage was, it will be very difficult to see the whole repair. That said, and to sound like an echo from the rest of the guys, there are plenty of 150's out there. Another thing that might just get you over the edge of decision, pull out the seats, take up the carpet enough to pull the inspection panels up over the landing gear and take a good hard look at the gearboxes and surrounding area. The older 150's with the flat gear can take a pretty good licking, but are also known to aquire damage to this area so if the seller won't let you look into this area, don't even hesitate to walk.
Also, about the stain in the back, you should be able to crawl far enough back there to take a good look at it and see if it's corrosion or not. Just be sure to put a stand of some kind under the tail skid.
Jay Shealy
N66088
