I did it on my '87 a few weeks ago. On mine, I had to take a die grinder and grind some little 1/4" crescent-shaped reliefs on the top edge of the swing arm, at the front where the shock spring got closest to the swing arm. Without doing that, I couldn't quite get the bottom shock bolt to line up. Others haven't had that problem. You'll see what I mean when you get it in there.
The other thing you'll need to do is to relocate the reservoir. On my warrior the old shock one was mounted on the right side and had a fairly long hose. The Raptor hose is much shorter and come off to the left. I used the clamps from the Warrior and drilled a couple of holes in the plastic just below the seat and mounted it there. It sits right in the corner where the body plastic curves out into the rear fender. It looks good and is out of the way.
One more tip is to remove the bolts holding the air box to the frame. That way you can push the air box up and out of the way in order to get the shock into position. You don't have to remove it completely. You can get it in there without doing that, but it takes some manuevering. If I did that first it would have been a lot easier.
The bolt sizes are the same so there's nothing to do there. It rides much better and sits a little (inch or so) higher when unloaded.
John