Your comment got my curiosity up so I did some digging.fools sulphur said:White lightning make a touch hole insert thats drop in for the thompson center. I don't think they make one for the lyman.
...
Jim Chambers company which makes the White Lightning vent liner has always used a special thread pitch on their liners.
It has 32 threads per inch so the choices available are 1/4-32, 5/16-32 and 3/8-32.
The Thompson Center guns use a 1/4-28 pitch thread.
According to everything I can find, Chambers has not added a 28 thread pitch liner to the White Lightning series of vent liners so, the only way to install one of his liners would be to drill out the existing vent hole threads to the next larger size and then to thread it with a 5/16-32 tap.
The White Lightning vent liner has a hollowed out area on the side towards the bore.
This hollowed out area removes most of the length of the vent hole leaving about 1/16" of wall thru which the actual vent hole is drilled.
There are several other companies that make vent liners with hollowed out areas similar to the White Lightning liner that offer the standard fine pitch threads like 1/4-28.
These would fit the Thompson Center guns but they are not the real White Lightning liners.
The bottom line is, no, there are no real White Lightning vent liners available that will directly fit into a Thompson Center or Lyman flintlock gun without modifying the gun.