I would think the only difference is the holes for the plate to go, and of course, the light that would be above.
EDIT: I would think you should be able to drill a pair of holes in that black trim piece on the rear deck and mount the plate right to it. To light it, I would personally use some LED 'bolts' to get the job done. I used some that I found on ebay for ~$7 a pair and they do a great job, clean look to them, nice bright white light.
I recently did the opposite (internal to external) and have everything you would need to put the spare inside. Internal carrier mount, interior panel with cutouts, if you need the parts, I would be interested in working something out for your interior panel that doesn't have the mount cutouts. Not looking to profit, just looking to get what I want :giggle:
Is there a particular reason why you want to? IMHO, if you haul anything at all, the spare takes up tons of what is already limited cargo space. I couldn't even lay my set of golf clubs down in the back of my truck when the spare was inside. We tried to use the truck last summer for a family reunion and golf outing, 4 people and 4 sets of clubs, plus luggage and a cooler, HA! We were dreaming.