HOT302 - Did you ask the owner about the rear bumper? Did GM stamp date codes on bumpers?
Very rare according to this:
I think the date code occasionally popped up on some of them - I had the occasion to help a friend with a 7000 mile original '68 SS car, a survivor that was featured in one of Hooper's books because of the frame markings, original Corvette Bronze paint, and extremely low mileage and originality. To make a long story short, my friend proceeded to re-chrome parts of the trim, including front and rear bumpers and the guards through Advanced Plating in Nashville, with the car stored at my house while waiting for a local (and talented) painter to touch up the car. When we removed the rear (and detached the center bracket from the bumper) it exposed a date stamp (impressed) on the back side of the rear bumper, an April '68 stamping (car was a May or very early June car if I remember correctly). First one I had ever witnessed, and unfortunately before cell phone cameras and even my first digital camera came into being, but it was there. Moral of the story - I should have discouraged him from even touching such a low mileage example, but he was really obsessed with a blemish free car. And he eventually got it - before he sold it. True story -
