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
"They say the test of literary power is whether a man can write an inscription. I say, 'Can he name a kitten?'" -- Samuel Butler