To Daleleo: I had the same problem and more. Both the Stealth Rack and the Tour Pack Rack were too wide. I was able to bend them slightly (use a Vise, carefully) to make the docking points slightly narrower. The real problem was the length. After finding that I had to remove the rubber cushions from the forward docking points to get the locks to engage, I went to the dealer. Removing the cushions allows the rack to vibrate just enough to be audible. The dealer was able to get the locks to engage with the cushions in place, but this caused the black plastic pieces on the docking points to break. He replaced them and said he would continue to replace them if they kept on breaking. Seems the HD Engineers got the dimensions slightly wrong on the length. I have a feeling the dimensions used for manufacture were before plating, I have made this mistake when I worked Design/Manufacturing Engineering. There is no fix for this unless you want to grind the slots on the rack(s) which will break the palting and will eventually rust.
To Sun Devil: you can install the Stealth Rack and the Passenger Back rest at the same time with the four point docking system. I did not have any problems with the Passenger back rest but did have issues with the Stealth Rack, see above.