OldIHC

So I think there is only one way the gasket can be installed. There is flat side and a profiled side to the gasket. The flat side will not fit into the groove on the cowl therefore theprofile side goes down into the groove.
Based upon this then the lip of the cowl vent lid presses against the flat surface of the gasket.
OR
Does the flat surface of the gasket get glued to the bottom of the lid and the profiled portion of the gasket straddle the raised inside lip of the cowl?
It was late when I finally got it all diassembled and only spent about 10 mins investigating the gasket. I was hoping it was stupidly obvious but maybe not

I think Nikki, suggested doing just that. Glue it to the lid, and make sure it "fits" in the groove. That way, as he said, it will not catch water and hold it there. Just make sure your drain holes are clean and open from time to time.

Nikki was referencing L, R, S, series gasket/vent, KB is a different animal,

the reproduction gasket is not an exact fit, it goes profile down flat side up,

you have to use adhesive, I used black RTV, first blue tape all around vent opening to protect your paint if silicone oozes out, then silicone gasket, you have to stretch it slightly in spots, once you have it placed good blue tape it so it dosn't move,

reinstall the vent cover, insert pins, springs washers, new cotter pins, install handle and retainer springs , adjust handle to it pulls and holds cover down tight, it eventually will form a indent into the rubber,

helps if rubber has been heated warm as it is softer than when cold, once silicone has cured open vent and remove tape, clean up any oozed silicone,

done this on a few trucks, just did my KB-1 panel this last summer,

Thank you. Thats exactly what i needed to know.