The older 1100 barrels used a thinner ejector, so you may have to open up the slot in the 1100 barrel for clearance.
The groove for the O-ring are in slightly different positions. Most of the time it makes no difference. Sometimes two O-rings will make it work. Sometimes they just don't work. I suspect tolerance stacking is the culprit.
Short answer, I would not buy a barrel expecting it will work, but if I had access to a barrel I would try it.
I have a step rib 11-87 barrel on one of my Remington 1100's right now. It works just fine. I also have an 11-87 sporting clays barrel that I use from time to time on an 1100, no problems there either. I do not have any 11-87's, so I can't say if the 1100 barrels will work on them.