Why Revell made the upper fuselage of their X-wing for separate pieces, I have no idea.
With my Red 5 build, I basically waited until the end to put these pieces in place. Not this time.
Since I’m correcting the weird stepped panels anyway, I have to do the same thing on the three forward fuselage pieces. So, I decided to glue the three pieces to the lower fuselage half. I made sure that I lined up the upper panel lines. (This is a nightmare of you wait until the of your build, as I found out.) You need to remove the protrusion that extends from the main upper fuselage part. This is the part with the cockpit, droid area, etc… It doesn’t serve any purpose any way. Take your handy dandy razor saw and cut it off.
I have the pieces attached to the lower fuselage half. I will end up rescribing a lot of this area due to removing the inaccuracies and smoothing out filler at the join areas.