Gas tank to cab seal

[dgrinnan]

I have a new gas tank and just order a new gas tank seal for where the filler tube comes through the floor into the cab. It is an inch or more think piece of foam.  My question is where does it go.  Is it supposed to fit between the top of the gas tank and the bottom of the cab floor?  That appears to be the most logical location.  I do see what appears to be screw holes around the perimeter of the opening that may me think there is suppose to be a metal flange also on the inside of the cab. 

[JBNeal]

additional information - cab floor to fuel filler neck seal

[dgrinnan]

Thanks.  This confirmed what I suspected.