Hey, welcome to the Site!
Yes, that is one of the things that is not reproduced yet.
A lot of people replace that light panel with a 1970 panel, I guess because 1970 challenger is more popular or simply because the 70 repop is easily available.
Now, as unfortunate as that may be, those 72/74 light panels that are removed to be replaced with the 70's light panels sometimes come up for sale on this site.
Just be patient, the members /their projects and the swap meets they attend will turn something up for you.
At any rate, that panel won't stop you from advancing your project.
By the way, a post in the welcome wagon and some pictures of your challenger would be a nice start.
The best of luck.....