Verts and coupes will have diffrerent spring rates on the rear springs to compensate for the 100-200 lbs. difference between the two types of model cars. If it says they are for verts, then they should only be put on verts as the rear end would be higher on a coupe. Depending on the amount of drop that the spring will give you, this could be as much as an inch difference between the front and rears.
I put Steeda sportlines for a coupe on my vert, and they were about 3/4" too low for my liking. I wanted to get some rear LCA weight jackers anyway to raise the rear a bit, but keep the car raked somewhat. Either way, I would have had to get the weight jackers (coupe or vert springs) to get that look.