timing cover dust seal vs gasket

[bumperbozo]

can anyone tell me the relationship between a timing cover dust seal vs a timing cover gasket? are they both supposed to go on at the same time or is the latter an economical replacement for the former?

my dust seal doesn't seem to want to go back in place on the lower timing cover. the rubber appears to be too long and big near the bottom and just pops off when i try to tuck it in. i think oil contamination causes it to expand?

the timing cover gasket i got from toyotapartszone is these three cheesey strips of neoprene foam. i don't really see how they are supposed to be installed.

update: i ended up just using a razor to excise a few millimeters out of the old dust seal. the foam strip just looked like a liability.