These sights do fit the Rock Island 1911's with GI style sights; not the tactical model with a dovetail front sight. You must grind out the tip of the old tenon inside the slide a bit and then pull it out from the outside with locking pliers, etc. Be careful not to grind the slide itself. Next insert the new one and carefully use a punch to peen it and then grind it flush with the slide again. The rear is a bit "crush fit" but this is intended. Just be careful with the tritium gas vials so they don't break. These sights are 10x better than GI sights! The white ring around each vial makes for a sharp contrast and quick sight alignment.
Pros: They fit with marginal effort
Cons: Finish is lacking a bit.
This review was written in the old system and had content requirements that are different than reviews written today.