Drive by Wire

Hello to everyone from the New Guy in Town
I just got a van conversion on a 2006 Chevy Express.
When I was first looking at the vans the dealer told me the models with a locking diff also had Drive by Wire which I assume is electronic throttle.
How can you tell?
There is still a cable from the pedal to the throttle body.
I called my local dealer and he said it has it and any cables I would see are for the cruise control.
I thought the idea was to get rid of all cables.
And anyone know what lamp fits the underhood light? This one is missing and there is nothing in the owners manual like there used to be. Plus I looked it up in a Sylvania catalog and it said a #561 which does not fit.

Thanks for any help