All the fasteners are the same. The eggcrate underneath should be the same. There might be a couple of metal braces that are different, but should bolt on without mods.
The bumperpad eggcrate will be shaped differently from the 87-88 eggcrate.
Also, the bumperpad nose will have grooved trim, while the 87-88 will have smooth trim.
There were actually two aero (GT style) bumpers. One for smooth trim cars (86-87-88 GT) and one for grooved trim cars. (84 Indy, 85 GT, 86-87 SE.)
I believe the grooved-trim aero bumper has a piece of grooved trim molded in between the marker light and wheel opening, where the smooth trim just has a flat piece of plastic. (The smooth trim section between the light and the wheel opening is actually part of the light assembly.)
And yeah... the only bumperpad car to also have a V6 is the 85 SE / 2M6. (Some people compare it to the Formula.)