Installing Bakflip F1 - Do I need the shims?

[Mossyoakglock]

I got a Bakflip F1 for Christmas and want to get it installed this week.

Truck is a 2008 Silverado CC w/ shortbed. I also have the GM factory bedrail caps as well. Do I need to install the spacer and angle shims since I have the bedrail protectors?

On the Spacing & Shimming sheet it says that I need to install the spacer shim only on painted bed rails. Since I have the protectors I would assume that means that I don't need install those. It's the angle shims that I'm really questioning. Since the rail protectors essentially make the rail square, do I still need them?

There was a small note in the package that says "If your pickup truck DOES NOT have bed rail caps on the side rails...we have provided two ABS strips that must be installed prior to installation, etc....."

[mitchntx]

I installed Bushwacker rail caps long before I installed the F1.

 

I did not use the shims.