As I think back when I pulled out the original 350 some 38 yrs ago in the early 80s that 5th seal was in place on the drivers side and separate from the two smaller splash shields that bolt in between the inner fender and the brace. Of coarse being the stupid 20s something kid I was I pulled it off because it was in the way of the bellcrank lol. And the piece that it mounts to is long gone .