I installed an 08 on my 09. I did have to modify the tab that bolts to the frame in the center. ( Hacksaw). I would have to think that after doing that, the new style would fit on the old frame easily.
I installed an 09 Harley Mustache guard on an 08 Street Glide, with no issues. I have figured out the lower brackets were tilted different on the later (09-later) units, due to the new frame, and they will back fit, but putting an older unit on a newer bike, does not work without mods.