[A/S] Bedliner/Truck Cap Question

[RCPitt1@xxxxxxx]

Hello Group,

This doesn't directly relate to Airstreams, but I know many of you have tow 
vehicles (pick-ups) with and,presumably, bed liners. 

Question: Is it acceptable in your opinion to mount a truck cap on a pick-up 
bed with an "over-the-rail" type of bedliner? Or should only an 
"under-the-rail" liner be used so that the cap always mounts directly to the 
sheet metal rail? 

Thanks for your wisdom.

R. Pittenger
1973 20 ft. Argosy