You'll want to look for the VIN stickers on the various body panels.
That will tell you if there has likely been a repaint or potentially
body damage done to the car.

There should be stickers on the underside of the hood, inner portion of
each front fender (viewed with the hood open, in the area where the hood
seals), front nose cap (viewed with hood open), under side of each door
(viewed with door open), and underside of trunk lid.  It's been several
years since I had a Mustang, so those are all the places I can think of
off-hand.

You'll look for a sticker with the VIN on it, in each of these places.
If you find that it has been either painted over or the sticker has
something like "Ford DOT," then you may want to ask more questions about
the car.

When repainting, most shops will just paint over the sticker.  At best,
they may mask it off.  If the entire body panel has been replaced, the
replacement panels have the "DOT" sticker.

Steve
72 Skylark Custom455