It will fit if you fabricate some brackets for it.
It's just my opinion, but it will look goofy. '88-'98 stepside rear bumpers are the same as the fleetside rear bumpers, other than the shape of the notches cut into them for bedside clearance. So it is a full-width bumper, where '67-'87 stepside rear bumpers are narrower than a standard truck bumper.