It is not all the books, the only cut down MA5 is the MA5K, which is more like an automatic mini BR w/o scope in its basic form. It was seen mostly in Onyx, I do not know if it was mentioned in Cole. Now could I see adding a scope to that? Not really, that is not really what it was designed for. Now a red dot sight on the other hand would make sense.
However I do not think Bungie will ad such a thing, and I do not think they should. Halo MP is popular because of how it works now, if the screens are real and the poster is telling the truth then the "perks" will probably be the only MAJOR gameplay changes. Sort of like going from any other Halo CE to Halo 2, or Halo 2 to Halo 3. Only one or two major gameplay tweaks, the rest is all new/changed guns and new maps, along with much more minor tweaks.
That is what I am going to guess. If they added any the weapon upgrades on top of perks the game will look way too much like Halos only real competitor.... but what keeps Halo up there is the difference in gameplay.