Re: Well I wasn't planning on installing an inside mirror....
Check your state inspection manual, it may differ in language from the actual laws and you could fail with something that's not illegal to drive. For example, it may say something like "all original mirrors must be present or replaced in kind, and must be unmodified"...or it may only say you need a good view to the rear.
Re: Well I wasn't planning on installing an inside mirror....
sounds like you just need the internal rear view AS LONG AS you can see out of it (ie not a car filled with stuff or towing anything that obstructs the rear) then you would need an outside mirror.
IL law is different you MUST have an inside rearview AND drivers side outside mirror. Passengers one is optional.