Hi,
I have changed mine in the past and everytime I had to reuse the metal lock insert into the new sockets unless you have a source that works out of the box as i have not found a set from Napa or anyone else as of yet
as for lighting, all 3 light up with running lights (lights on) and the outer 2 and inner 2 light up with the brakes and 2 outer per side with turn signals
I have in the past swapped out the middle sockets with brake/turn signal (or 2 wire) sockets and had all 3 on each signal and all 6 with the brakes
I meet a GS owner who had a interesting idea of hooking up a set of ford sequential lights from a old t-bird which would be kind of neat not sure if the guy ever did
good luck with the lights as they can be trying to get them all to work, also keep things secure in truck as I have had the sockets get popped out in the past really not good in front of the cops ha-ha
Jim