I looked at an 1980 450SEL today. It's a non runner with all the glass smashed out including signal lights, headlights, etc., but the body & interior appear to be in decent shape. Dark navy blue w/ black leather interior and unusual black bundt rims. What's a unit like this worth? I know it's a hard question, but would I be out of line or out of my mind to offer $500 for it?