FO only, must have an IR, MCC and full set of ATPL written passes both to do the type rating, and to fly as crew.
I'm not sure I've seen the regs, but I *think* that in an aeroplane certified for single pilot ops (D228 for example) but electively flown multi-crew a "vanilla" CPL can be type rated (if a type rating is required) fly either seat subject to their licence limitations. Not sure what happens in that case if, say, shooting an approach where only one of the pilots has a current IR - presumably both continue to log but only one logs IFR?
G