At one time, Track of the Wolf had a line of advanced projects kits that were based on Rifle Shoppe parts. That included the Brown Bess kit. I know that when I built my Harper's Ferry 1803, the parts came from the Rifle Shoppe. My lock was assembled by the Rifle Shoppe and the rest of the parts came from Track.
Over time, Track established its own line of advanced kits. I am not sure who is the source for the parts. I do believe that the Track of the Wolf's parts set for the Long Land Pattern is a reasonably good set of parts. As with all parts sets for any specific firearm, expect to do a lot of work to get the final result to be an accurate and correct to pattern version of the desired firearm. Any kit builder will need to have a lot of source material to make the necessary adjustments to the kit. Not exactly a first time builder's recommended build.