2014 GMC Sierra Stake Pockets
 

I'm mounting a ham radio antenna and a CB antenna in the stake pockets on my truck bed, but wondering the best way to run the coax. I'm aware of the rubber grommets on either side of the cab, but how do I get the coax from the stake pockets to exit below the bed?

Update
 

Well, I got my antenna mounted in the stake pocket and have run the coax down under the bed. Now, however, the rubber grommets that I was told led in to the truck cab can't be found. I've lifted up the plastic edge pieces and run my hand under the carpet looking for the rubber grommets. I've crawled under the cab looking for them from beneath.

Can't be found. Can anyone help me?