Propane Locker Gasket

[KWKloeber]

ABYC A-1; 1.8.1.4 -- shall open only from the top with a gasketed cover that shall latch tightly, and...

Not for vibration, for sealing.  Give propane a lot of respect, a belt-and-suspenders kind of respect!

-kk

Like I was saying.
You don't need an air tight gasket on a box that is already vented.
Any type of rubber gasket will do the job.
The gasket is there more to prevent vibration of the cover and make anoying noise.
It as no sealing purpose.