I just went through this with my dealer. I purchased a new 1500 bighorn that was on the lot. It had the important features that I wanted, which included the RAMBOX as well as the BUG.
Wouldn't you know it, when I went to pick up the truck, I asked the salesman to demo how the extender is mounted and of course it was missing the mounting hardware as discussed in this thread.
He said "oh yes, I remember seeing a written notice that the 'extender' feature was dropped because someone lost a load of cargo and sued RAM over this. So they pulled the feature and now all the brochures, have been amended to remove the word "extender".
I also asked about the retractable bed step, as I wanted that also. This was also removed from all the catalogs, and parts can't find a reference to it. So I can't even order one if I wanted it. I'm not sure of the reason for this.
One thing that was strange to me, while I was shopping for trucks at different dealerships, I noticed that the tie-down mounting rails were all anodized black, which I thought looked great. They sort of disappeared especially on the trucks that had the spray-in bed liner. But on the truck that I picked up, the tie-down rails seemed to be anodized silver, which is a contrast to the black truck and black spray in bed liner. I tried to ask if it was a mistake, but he said no, that's how they are. In fact, another slightly older truck parked next to mine also had silver tie-down rails.
Does everyone have silver tie-down rails? A black set would look much nicer IMHO. Perhaps my memory was wrong as to what I saw at other dealers?