The body kit I got was not factory, I got it from MSA (
www.theZstore.com). It is the xenon urethane body kit for the 84-86 Z31. I don't believe it will fit on an 87 because of the different nose and fender flares of the 87+ Z's.
However, MSA does not have any kits for the 87+ Z's but the following link does.
http://www.kaminari.com/catalog/33