I did that mod on my first II (I think it was back in '86 or '87..god I'm getting old
]) Anyway, mystang77 is right, the lenses are all molded together so you will need to cut apart two sets of lights. I used a fine blade hacksaw blade, then I reassembled and glued it all back together. I used crazy glue but I'm sure there are better adhesives available. I then carefully applied clear silicone over the joints to make sure moisture could not get in. As for the wiring, I got rid of the back up lights andspliced it in with the turn light so both bulbs in the middle worked. Not the only way to do it, just the way I did it.
One thing to do is shop carefully for your second set, sometimes the red fades differently from car to car. When I did mine I found the first set ofjunkyard lenses I used were so far off I tossed them and found another set that matched better.
Francis "Turbo II"