Last year I "built" a Traditions Kentucky rifle from one of their kits. It's one of the European made kits and the lock that came with it is a two-bolt unit, one in front, one in back. The lock isn't high quality compare to Siler and others but it works. Whoever started on yours may have seen a lock mounted like my Kentucky rifle and thought it was the right way to do it.
I also agree with LAGS on gathering all the info you can before buying parts or working on the kit. Having a solid plan in place before hand saves missteps down the road.
Also, lipstick can be used in place of inletting black. I did a second rifle last year that I built from ebay parts and a plank of tulip poplar from a tree I cut down in the yard and it worked fine for me.