My WINEGUARD BATWING antenna on my fifth wheel trailer has a raised metal piece with outside ribs mounted on the roof to align up with the main bars of the BATWING antenna when it is in its down position. This is the only part of my WINEGUARD antenna that touches the roof area. The BATWING head and antenna is a couple of inches above the roof when in the down position.
This also keep the wind at highway speed to not move the antenna around when in the down position.
Just figured other WINEGUARD installs did the same thing...
Roy Ken