I have saved this just for this question, it comes up fairly often;
I hope you understand these "kits" offered by Track of the Wolf, Pecatonica River, Jim Chambers,Muzzleloader Builders Supply, etc are far from a easily built "kit". In fact, they could be more properly called a "box of rough parts". Absolutely nothing will fit in the precarved stock. The suppliers of these kits will do any or all of the assembly for you all the way up to a gun in the "white" or completely assembled and only needing wood and metal finish.
The only things that come close to being finished parts are the lock and the trigger. Even these parts require locating, drilling and threading the holes for the screws that hold the parts to the stock.
The barrel is not finished. It is rifled but the sight dovetails are not cut and on many of them the breechplug is not installed. This applies to the trigger guard, butt plate, side plate too. These are just rough, unfinished sand castings.
All of the parts will need to be inletted into the wooden stock. This applies to the barrel, lock, trigger guard, butt plate, side plate and ramrod thimbles.
Speaking of the stock, even it is just a moderately close roughed out blank which will require a LOT of wood removal to be close to the real longrifles.
Knowledge of metal and wood work is a definite requirement.
Plan on spending a minimum of 120 hours of your time to finish your gun. Actually, for a first build, a number like 180 hours would be closer if you want your gun to be something you can be proud of.
Kibler kits are a big step up from a parts kit, all the wood shaping is done but the inlets are a little undersized so you have to fit the parts. The metal is rough castings so you have to do the finish work. All the holes are drilled for barrel lugs but you do have to install and drill the lugs for the barrel and lug holes for the trigger guard. The barrel will need to be draw filed and have the sights installed in the precut dovetails. Your finished gun will be very period correct.
I'm not telling you all of this to discourage you. I just don't want to see anyone go into this with the idea that the gun will be ready for assembly.
Speaking of ready for assembly, Traditions, Lyman and Pedersoli offer kits that are easy to assemble and finish.
These are basically the same guns these companies sell but the parts don't have their finish sanding and finishing done.
These "Big Factory Kits" are indeed, true "kits" with all of the threaded holes located and finished.
They require something like 15-30 hours of your time to finish depending on whether you wish to make modifications like reshaping the stock or installing inlays or wire inlays.