It doesn't matter what the mileage is. Are you having Fun?
More than likely, I would guess, 100K Plus.
In your pictures, it looks like the rear quarters have been replaced. The Sides do not have the wheel opening arch that the front has. Also, diamond plate rockers... Probably been patched or covered up.
I hope you don't take any of that the wrong way, I'm just pointing out what I see and think.