Hard to say if the fender tag is original or not; looks original (to a 383 Cuda) but you need to decode it and see if the options add up (are present on your car). This isn't 100% either as there are numerous stories of original tags that didn't match the car exactly (more or less options).
I have the tag for my Cuda but nothing for my Challenger. I had a tag made but it is not exact. I would like to get a faux tag made for my Cuda listing the new build with made up options like 416 engine, 4 link, spoilers, etc. Basically a clearly fake tag but a cool conversation point when the car is done. I even thought I would do a second tag (like a Hemi fender or trans am tag) that says "Special Build by xxxxxx" or something.