I don't see how the CP3 can limit RPMS. From what I understand it is just a pump tied to the engine that creates rail pressure and has no way to cut fuel at a certain rpm.
The pump overspeed limit is at 4000rpm. The injector overspeed limit is 3500rpm. It's the high speed governor that limits the rpm at 2600 rpm and several settings that need to be raised to reach 3200.
I've tuned one of these to rev to 3200rpm and a 6cyl with this same ecu to 3500rpm. Besides just raising the limiters, there are several maps that end just over 2600rpm that I've also re scaled.
The ecu controls how much pressure the pump puts out, so it could definitely limit rpm. However, I doubt that is what they are doing. The rail pressure map maintains pressure to 2900rpm and then at 3000rpm it drop way down to 25mpa.