American Tonneasu Tri-Fold gap?

Howdy-

I've searched and can't find the answer. I have a chance to buy a American Tonneasu Tri-Fold cover for a good price. I tried it on and there is a nice height gap between the front and the cover and the rear and the cover (almost a 1" gap) of my truck (15 Sport Access Cab). Part number seems to be correct (66405).

Do I have to take the side rails off? Anyone have a similar issue and if so, how was it fixed?

Thanks.

 

I bought one when I got my truck in 2012. It's now on my BIL's 15.
IIRC, the gap in the front needs to be built up with self sticking foam weather stripping.
The gap in the back part that rests on the top of tailgate was sealed by a self sticking rubber strip.
When the rear part was clamped down. It sealed up fine on the tailgate.
Are you missing these?

 

I think so- I just didn't know what is what it was for- thanks!!!

 

No problem.
It also came with a roll of self sticking rubber "tailgate seal".