[TheApocalyptican]

Ok, so after some extensive research, the difference in the aftermarket(OE might be different) is that the non-ac top shrouds sit lower, and use a bracket that attaches to the back of the core support, whereas the top ac shroud sits higher, and uses the bracket the goes over, and attaches to the top of the core support. Also, the non-ac top shroud is meant for the short 17" radiator.