I have an 87 coupe with the round molding. In the Process of putting the GT nose on it, but I need some help. I am not sure what year my new front end came from, the very end of the molding is ribbed and not removable. Also the side markers from my 87 do not fit, are they different for the GT front?

The AERO fascias that originally came on a ribbed molding car, have a portion of the ribbed molding actually molded into the fascia. This location is about the last 3" part that is closest to the wheel well.
The triangle towards the nose is removable and has smooth and ribbed versions.
The ribbed side marker lights are shorter due to this molded in ribbed section.
The smooth moldings are about 3" longer because this molded in section does not exist on all fascias designed for smooth molding (87/88 coupes and Fastback GTs)

You can take a ribbed molding Aero fascia and cut out the molded in ribbed section. Then you can place the smooth molding right over the top of this cut out. This mod will convert a ribbed AERO fascia to a Round Molding Fascia.

You can see the 3" section removed from this pic: