Its exactly the same as the other two lights. I just used the OEM hole to mount it.
Removed the outside flasher, mounted the rear light on the inside and ran the wires down through the inside and then remounted the flasher. I did have to open up the large outside hole (hidden by the flasher when mounted) a little to get my socket in the hole.
Removed the outside flasher, mounted the rear light on the inside and ran the wires down through the inside and then remounted the flasher. I did have to open up the large outside hole (hidden by the flasher when mounted) a little to get my socket in the hole.