Their e-mail support is stupid fast. I have not checked myself on my truck, but hopefully someone here can figure it out for everyone concerned about it.
Reply from their support staff, with regards to swapping the stock shark fin for the UConnect 8.4/RA4:
"If you can somehow pull down your headliner and check to see what cable is leading into the antenna we could give you a legitimate answer.
If there is a single yellow connector coming off the antenna then yes our antenna will work perfect. If there are two connectors (yellow and white) then unfortunately it will not work."
My dilemma as well: