"Loading: Firearms must load from the muzzle. Firearms which can be loaded from the "Cannot be loaded from the breech in muzzleloading seasons" breech are prohibited"
I'm not from Colorado but.. any muzzleloader that loads through the muzzle is fine. A rolling block or sharps etc that loads through the breech is not. If you are meaning could I purchase a breech loader and then load it through the muzzle and still be legal, I would guess NO!
We have some Colorade elk hunters on the board and they will make sure you get it right. Good luck with your elk hunt. It sounds exciting.