If you don't have any luck on here, try looking on etrailer.com. I had no intention of pulling a 5er with my truck but, I know when looking at the different models it listed if it would or wouldn't work with a 5th wheel hitch installed. With regards to my truck, I know the Firestone's would work but, the Airlift brand wouldn't.
Even if you aren't sure or don't get information you can even send those guys a message on there. They are quick to respond and will help you out, even if you don't buy from them.
2012 Keystone Sprinter
Still sticking around for the good people and advice.