As I understand it, the rubber "flap" seals that goes around the slideout is a secondary seal and doesn't do much in the way of air sealing. It helps keep driving rain and wind from getting to the primary seal.
The primary seal is more like a door gasket and is located on the slide room itself and it compresses against the inside edge of the Coach wall when the room is fully extended (or the outside edge of body when the slideout is Retracted). If the room doesn't extend far enough out, that seal does not get compressed and you can get leaks.
The rollers on the bottom are used to adjust the slideout (top to bottom) so it sits in the body opening evenly (same gap at top and bottom) but doesn't have much effect on the sealing of the room.
If you run your finger past the flap seal to the edge of the slide room you should not be able to get your finger easily between the slideout seal and the body it presses against.
I noticed my front curbside slide was not compressing this seal evenly (gap at bottom sides) when the slide room was fully extended. I spoke with Paul at HWH about it and he suggested I adjust the room so it compresses this seal a little better.
At least that is the way I understand it. Here's a photo of this seal (for my '05). I don't know if the design changed after 2005.