FanTastic Fan Gasket Question

[Swrider]

Hello everyone, just a quick question concerning the installation of a FanTastic fan.
I called vintage trailer supply wanting to purchase many things to help seal up my new '72 Ambassador, such as window gaskets, which they don't have in stock, sealants and butyl tape.
Now I have seen a couple of videos on how to install them, and I was ready to install mine using butyl tape as an adhesive between the fan and the aluminum, and then seal over using 3M tape. But the helpful lady at VTS asked my why I wasn't using the gasket included with the Fan...
And I was stumped? What gasket is she talking about?
Well she clarified by informing me that the white pressed foam which I, and apparently many others, thought was just packing material, is actually the gasket to use. But I haven't seen anyone else use it, what gives...

[Al and Missy]

The foam will compress with heat and age, causing leaks. Your plan is better.

Al

[Aerowood]

Ditto

[Swrider]

Alrighty then, thanks [emoji16]

[kidjedi]

I had the same question when installing mine, and after a bunch of online research, I went with butyl tape.