I don't know if it would fit on a 3rd gen 4Runner, but AFAIK it would bolt onto a 2nd gen. Couldn't say for sure if the rear valance would have to be trimmed, but on a pickup you have to cut notches to clear the mounting brackets.
'91 Toyota Pickup
'09 Kawasaki KLR650
'12 Gunnar Rockhound 29
“Anyone who believes in indefinite growth in anything physical, on a physically finite planet, is either mad or an economist.” -- Kenneth E. Boulding