I was looking recently and if you look at some of the window stickers for the Rebel 12's now they list the 9 speaker system as part of the Rebel 12 package instead of the HK system. It appears that the HK system that was originally available became constrained in supply and FCA elected to offer the Rebel 12 package with the 9 speaker system. I assume the 9 speaker system is the Alpine speaker system but do not know for sure.
I was originally set on a red/black rebel 12 but that color was originally not available when the ordering for the rebel 12 package was opened up. I was looking last weekend at other color combos and when feeding the VIN# into the window sticker link it showed the rebel 12 package with a 9 speaker system instead of the HK system. The red trim around the door speakers was not shown on the interior shots of the trucks.
There were some cases of rebel 12's getting ordered with the alpine speaker system in addition to the HK system included with the rebel 12 package. It adds more cost with arguably a less capable speaker package. Apparently, the Red / Black color scheme was available for at least a few hours with the rebel 12 package as that is what the window sticker read.
One thing that is consistent so far is that the Rebel 12 package should come with heated leather seats. No tire tread pattern infills.
At this point, I'm waiting to see what the HD options pan out to be.
Some folks were very unhappy that the 9 speaker add-on for the Rebel 12 at additional cost deleted the HK 19 speaker configuration that was part of the package. The handling of the Rebel 12 edition wasn't handled very well in my opinion.
In my research I have where some owners are reporting the the 19 speaker system is underpowered by the amp. They were hoping that FCA would have a simple fix such as an update but you can squeeze so much power out of an amp. Although with todays technology i could be wrong. Im also uncertain of how big of a problem that really is as there isn't very many of the 19HK systems. There was one in Williston ND that I was looking at. I declined to pursue that option. So id assume its why the 9 speaker Alpine system was brought in. This is the system I have in my truck as I just picked it up yesterday. Actually they drove it to me since Im working and we swapped vehicles at a a gas station. Not sure if the HK would be mixed into an alpine system. Id think that would be highly unlikely. From what I can see is that 19HK system does come with leather seats and the 9speaker system does not. I have the 9speaker option. It would seem supply constraints has effected FCA from the start. A simple headlight lamp is nearly almost impossible to find as I saw guy hit a deer and his dealer couldn't get replacement parts. Found a dealer in CA that was willing to give up the ONLY one they had.