Are these Mopar performance gauges still available anywhere

That’s true. If you or I print it for ourselves or a few buddies, no issue. Gary or yourself selling at a profit, now there’s trouble. Getting a good printing is not really the issue I think though I wouldn’t know how to do it so the numbers are transparent and light up, not my field....
Printing on plastic...

Now how do you take the gauge apart to install new printed face?