I won't quote every response from those above. They all show a great deal of insight.
The original 1842's were .69 caliber smoothbore. I believe the 1842 had the distinction of being both the first percussion musket (the M1841 was a rifle) and the last smoothbore issued by the US Government. There was no rear sight, and the front sight was a brass bump on the forward-most barrel band. Rifle muskets shooting conical projectiles came later, and existing supplies of 1842s were later rifled to shoot a variant of the Minie bullet. They had adjustable rear sights added at the same time. The rifled version of the 1842 proved to be impractical. It just didn't work as well as hoped, and the recoil was unreasonable for the average soldier.
The question, as I understood it, was whether the smoothbore (with no rear sight) or the rifled version (with a military-style rear sight and rudimentary front sight) would be a better choice for hunting. May I suggest neither? We are talking about over ten pounds and close to five feet of gun here, in 14 gauge, with lousy sights on the one hand, and sights limited to a bump on a barrel band on the other. These are things to consider.
I have an Armi-Sport M1842, a smoothbore de-farbed by gunsmith Todd Watts. I love it. Some guns come and go, but this is one of my very few "keepers." It is a lot of fun to shoot... On the range. In its original configuration, it was designed as a military gun, and not a sporting arm. I don't doubt that game was taken with these guns in times past, but it would not be my first choice for taking afield, in its military configuration (many surplus military guns were "sporterized" for sale to the civilian market). If the M1842 were my only choice, I would pick the smoothbore, and work up loads for both ball and shot, and try to work on my hunting skills in order to keep my shots within "bow hunting" range.
This is not to discourage you. As I said, the M1842 is a great and historically significant gun, and as one who owns one, I can tell you it is fun to shoot and easy to maintain. It just wouldn't be my first choice for all-day carry in the woods in pursuit of game, with the hope of a humane kill. Others may feel differently, and I respect their opinions.
Best regards,
Notchy Bob