First I would recommend getting a couple books on building .
Then If your wanting old school as you say , then junk the idea of the TC � past being a side lock , there is not much �old school � there .
If it�s a � stock your looking for then I would recommend doing a lot of searching on line and building a file with folder of nothing but rifles that you like . Specifically those that fit what your looking to build . Save as many folders of each rifle that you can . IE patch box , side plate stock , barrle , sights ��.. You name it .
As was said , there are several places to buy parts from but when looking at complete parts assemblies . IoW Pecatonica , muzzleloader builder supply , Sitting fox , Chambers�. There are probably a couple 100 more that supply nothing but individual parts like locks , triggers or castings . Then you have the barrel makers Like Colerain , Getz , Rice , Long hammock ��
With assemblies and pre carved stocks be sure what your looking at is done for a small caliber IE the stock is proportioned properly
The other thing to consider is building from a plank and then buy parts from different suppliers . Frankly IMO this is the best route to go . The reason I say that is that most of the bigger suppliers like ToW offer only the most popular , handful of styles and the generic hardware for those styles