You'd never get away with it, For every month of each body plant the BODY tag stampings look different as the stamps wore (at differring rates, like the 8 wore badly earlier than others), it'd be impossible to do right. Plus you'd have to know what numbers went with what. This is why I keep numbers and trying to collect a full set of tags from each assembly plant for each month. The fake tags are a different allow and don't stamp the same as the real ones. What these original tags would be good for is to send off to get re-stamped with your original numbers if your original tags were damaged. Example, i've owned a 1977 308 auto LX SS for years. Tags are ripped badly where some idiot tried to steal them. I've been considering getting new ones made to replace the damaged ones. All i'd do is when or if I sold the car (it is only a crashed shell) i'd give the new owner the original tags so they could see for themselves the numbers are all correct.