I could not tell you for sure on a XPR, never had one open.
In the BPR sloppy soldering, and ALT. parts inside. And overall fit and finish was poor or just different compared to the original.
Also the guy who purchased the BPR knew it was a hack, but was curious to see what the difference's where because it was so cheap. If he would have bought it not knowing it was a fake, I doubt he would of ever known.
I would open it up and see if the LED's for the keypad are populated. If they are populated, could be part of the problem with the dim display, not sure though. As I am pretty sure all XPR's had a lighted keypad.
As far as the S/N , I am scratching my head too!