The original question was about stripped lowers, and for the time being, they are identical except for the markings.
As to what parts go in them, the only difference in internals would be the hammer. What stock you choose to use would dictate what you might need there...9mm buffer for sure...and if using CAR stock (or stock that uses CAR length tube), just a CAR action spring behind it. If using a rifle stock, or stock that uses rifle length tube, you would need the stock spacer to go in behind the CAR spring. Regardless of anything else, you would also need a 9mm magwell conversion block. If you were to purchase the 9mm complete lower half, then all you would need was an upper half and a magazine.