All metallic cars were painted, thus it is not uncommon to find imperfections. My In-Violet Cuda, Bronze '69 Charger, and Turquoise '69 Coronet all have blemishes. I've had others in the past.
I've talked to several people with painted blue '70 -'74 Mopar promos who have had the cars shatter when handled. The '71 Dark Blue metallic cars are said to be exceptionally brittle. Something about the molding and painting of cars in this color resulted in the cars being like hand grenades. Other blue cars from '71 and up are also quite brittle.
The '72 Challenger at left was MINT- literally looked like it just came off the assembly line in Mount Clemens. Except for the body, most of the pieces are still mint. Generally speaking, ALL painted MPC models are brittle. Unscrew the chassis at your peril!