As someone previously mentioned, 1970 Lynch Road built B-bodies did not have the tag secured to the inner fender when the car was painted. It was hanging from the upper roof rail or similar area. That means they did not get more than a dusting of paint on them. They were then secured with screws to the inner fender after the car was dry. They don't have the typical bend up because an inspector didn't have to do that to punch a stamp in it (if it even got one). Well since there is hardly any paint on the bare steel tag they were very susceptible to rust. Plenty of years of humidity exposure to be sure is going to degrade that tag. I'd be very suspect of one that that is smooth.