I’m aware of two original U-code N96 Challengers, Moparts member VCODE has one and will probably chime in when he sees this post.

Here’s a registry created by member “Speeddemon”

https://340shakerrt.wixsite.com/dcshakers#

And here’s the info from it on 440-4 cars (as of 2017):

440 RT
Eng Trans Vin Number Date Color Seats Roof F. Air Built
E86 D32 JS23U0E142... 504 BL1 H6E4 BL1 N96 U
E86 D21 JS23U0B372... 610 TX9 H6X9 V1X N96 U

It will be great to see more details on your friend’s car if it turns out to be an original N96 car.