I want to close the loop on my attempt to have the centerline added to my Longhorn (August 2018 build).
First, I provided evidence to my dealership service manager of three trucks currently in local inventory that have the 12" screen, surround view system, and centerline:
Putting this together with the information you all have provided on this and other threads, it looked like a simple update (swapping out the CVPM) would add this feature to my truck. Alas, this was not the case. My experience was as follows:
Day 1 (outlined above): A newer version of the CVPM was installed. The truck was in the service bay all day, as programming proved unsuccessful. This resulted in the loss of surround view and active guide lines.
Day 2 (today): The FCA field service technician was onsite, which we thought would be helpful. Instead, he chastised the dealership service manager for attempting this update and (they say) made the dealership eat the cost of the part and technician time. My original CVPM was reinstalled, restoring the surround view and active guide line features. No centerline is present.
I appreciate that the service manager was interested in helping me out and was willing to give this update a try, but I'm now in the same camp as
@Jus Cruisin - it's time to leave well enough alone.