2007 Silverado questions

[Zimcocomp]

I just bought a 2007 Silverado 3500 HD (new body style) with 6.0L engine.
I have two questions about it so far.
First, does anyone know if a cap from a 2006 will fit the 2007 bed or has the bed dimensions or cab shape changed?
Second, how do I tell it the towing gearshift works. I thought if I pressed the button on the shift handle an indicator would light up on the dashboard.
I think I have tried everything else to see if it works on the truck.

Thanks

 

[Zimcocomp]

I answered my own question about the cap. It will fit. I went to look at a 2006 and it fits so I bought it.