Yes you can add the LED chmsl cam, not cheap though. The easiest ways are using a lockpick or Jailbreak form customtronix.
http://www.ramforum.com/f41/third_brake_light_failed_--_dealer_only_work-65960/index2.html see posts 16, 18 & 19
Currently the OEM CHMSL cams are selling for around $275.00
The harness will cost you around $ 75.00
The lockpick will cost you around $425.00
RAX Jailbreak will cost you around $260.00 (silver)
You could buy the whole shebang fro Customtronix in their gold package for 699.99 euro or 790.00 us which also will include a front cam. The customtronix jailbreak is the most factory like and will actually add the softkey to the radio for the cargo cam.
Under Dash | Customtronix
The lock pick is more of a piggyback type system but offers more capabilities, but either way its exspensive. The other issue you may have is getting a brake light bulb out error, several ways to correct that as well. I designed a built a PNP error correction plug for that, using no resistors.
http://www.ramforum.com/f146/mopar_...light_cargo_cam_all_trucks-50773/index18.html
Being a 2016 you may be able to have the dealer add it for you. On 2013-2015 trucks equipped with both tailgate and CHMSL cams the BU cam was displayed in the rearview mirror, and the dealers could not do a OEM install. On the 2016 I am told RAM got smart and enabled the cam port in the radio similar to the RAX jailbreak and they display both in the radio.