I have a few friends with them. A couple that are stock, a couple that run in the 10s and make over 500 horsepower.
I would offer the guy 6k for the milage and see if he takes it. Doing some quick research on it, it's worth every penny of $7,900 but it doesn't hurt to try.
IMO that's a lot of miles for an LT1 car, as the optispark will go out soon, not fun to change. They seem to last for awhile though as most of the ones I found were >100k miles. Still though, doesn't matter what chassis it's in, it's still an LT1 engine and they are notorious for having problems.
Plus the tranny in that will not last a hell of a lot longer if it's the stock unit without a cooler. I ate up a 4l60e in a lighter Camaro SS (albeit more powerful motor) in about 75,000 miles. Couldn't be happier with my built unit
If you're planning on modding the piss out of it, probably a better platform as they are heavy ass cars, and for the money you will invest you will have a fun but minimal return over an f-body of the same year.
However! IF you are planning on throwing some wide rims on it (friend did 18x10 18x12 set up with a deep dish), and some mild mods, you can't go wrong with a car you can fit 5 big ass dudes in and take your buddies out for a night of drinking.
All in all I like them, but I couldn't own one that didn't have an LS1 swap into it.