Hi Steve,
This really has become a bit of a conundrum (no pun intended
, since you posted this interesting Native American knife. It is interesting that the word is now revealed as 'sound' which makes sense with the drum. I think the best course would be to check into history of utility cutlery, perhaps by finding the types of shears (you indicated these were sheep cutting shears) it might be possible to find early trademarks.
In searching for the history of merchant marks (as discussed on the trademarks thread) there are books and possibly sites carrying data on these marks.
Antique dealers who carry vintage tools and implements often have books of trademarks and stamps, so searching under those headings might be productive.
Wilkinson is of course a huge corporation which absorbed numerous smaller companies in the course of its history, and possibly might have such records. Frederick Wilkinson himself often posts over on 'antique and military swords' in the Sword Forum International site.
Wish I could offer more help...its got my curiosity going too!
All the best,
Jim