Just thinking out loud here, but there are some stong decorative similarities between Bedford rifles and those made in the Cumberland School. You might do well to check some of the Bedford guns that have a yoke type, tang inlay, (thinking of Stoudenour here). They all usually tend to be somewhat complex, but similar. So, you may find what you are looking for in that school.
If the outlines are indistinct, it must have been missing for a long time. Good luck!
Best-Dick