I bought my bird 2 years ago, similar mileage and also all original. Mine had no surface rust on the body at all and a fairly new paint job. The one on e-bay's interior may be in slightly better shape, but it's comparable. Since I was buying it from my Dad, we agreed to have it professionally appraised at an auto restoration shop. It appraised for $9800.
So this gives you a bit of a baseline.