[84LX89GT]

The '85 to '86 front noses have fender extensions that bolt onto the front of the fenders (which have holes drilled in them) that bolt onto the front clip. The GT front clip has holes for fog lights, whereas the LX does not, that is the only difference.
The '83 to '84 front nose is narrower and doesn't use fender extensions on the front (last years to not use them) and as such, if you got one of those you'd have exposed fender holes if you matched up the nose to the fender.
The '79 to '82 front clip have different hoods that don't come down in the front and i believe the '82 GT's have special fender extensions for their one of a kind front clip, but i'm not exactly sure.
The '87 to '93 front LX noses have fender extensions but i believe they may be shaped differently than previous years and the GT's of course have the large fender extensions as part of the whole ground effects thing that matches the nose.
The thing they all have in common is the mounting holes are the same to attach it to the vehicle, but the trim/hood doesn't match up on alot of them depending on which years you swap.
I hope this helps.....by the way, my '84 got converted over to an '86 front clip that's why i know all about the fender extensions