Are 88 RS ground effects the same as 85-90 iroc ones?

Would they fit on a 91 camaro with no modification?

Just making sure as Ive been surprised a few times with a lack of interchangeability such as when i tried to put an older upper dash in.

 

 

They will work and I believe they use the same mounting brackets. The self tapping screws into the wheel opening might be in slightly different locations, but no big deal to drill the new holes. Front nose is the same for 85-92, but the lower wrap around chin spoiler is specific for 85-90. Side rocker and door ground effects should bolt up and rear quarter panel sections as well. The rear bumper cover will need to be swapped to the 85-90 version as well since the lower ground effect section is not separate. Good luck.