That engine pic you posted isn't exactly ''period correct''. When Kenne Bell was selling that contraption (worth 2 tenths and 2MPH) the translator didn't exist yet. That pic has a 3" MAF pipe that necks up to a 3.5" LS1 MAF and then necks back down with some sort of custom hose to hook it to the 3" filter.
There are no seals or plates or anything because like I said that's not a ram air system. They even put slots on the bottom to bleed off any pressure it make make so debris can fall out. You're just going to have to take your specific MAF pipe and MAF and make something that lets them all bolt up.
Honestly if you're worried about the filter being exposed, you're better off putting that cannister on Ebay. (With any luck the guy that paid out he nose for the KB pressure gauge would bid on it).
A normal filter on the cold side of the firewall gets loosely exposed to road elements swirling around in there.... Those type systems get road elements sprayed directly on it. I've got an ATR 'ram air'' with a 14" filter that came with my car. You could see a definitive black spot on the filter where the inlet tube was. (It was also proved to be a restriction back when the average modded hot street car were much slower).
That reminds me, I need to get off my butt and install my 'earlbrown bigass cold air kit' and put that ATR on Ebay.......