yeah i can only really give you guesses about this stuff call them for real answers. Be sure to mention that your a repeat customer when you call and i'm sure that they will give you a break.
you could always just remove the wire and socket and bolt your old one into the new reflector, might be a little harder with the cool tube. Decideing which to get is a toughie, i had a diy cooltube for awhile that i made from a pyrex bake-a-round, it worked alright, but it was much smaller diameter then a real cool tube and i think that was holding me back. Also i had no internal reflector so that sucked ass. But that one looks nice.
I now use a reflector nearly identical to the one in your original post, works great after you go over all the seams with foil tape to prevent air leaks.
No matter what you choose you will be happy i'm sure.