Sorry Bruce, that is nothing like what I believe Busse would use.
From the link, those appear to just be some sort of "Rasp Sticks" or something. They are calling them files for checking hardness. Those would seem too inacurate for what a good knife-maker needs. Even many small custom makers have better, more accurate and more capable tools.
I would be VERY confident Jerry would use a WAY more advanced method for checking hardness.
I think the "Indent" methods of testing are referred to as "Vickers" Hardness Testing tools or similar. The defice is pretty highly precision!
I don't have time to do extensive post or more research, but notice at the following link how the machine is capable of hardness testing in patterns such as: "zigzag" and other patterns of hardness testing via indents.
Vickers Hardness Test Equipment I don't know "Exactly" what type of machine or brand Busse uses, but I would tend to believe the "Method" is most likely the "Vickers" Method or "Brinell" dent method rather than some scratch stick/rasp/file tool.
Further, a rasp/file would not leave the "Tracks" found on Busse blades. A rasp or file would cut a groove. The "Tracks" found on Busse blades would most likely be caused by "Multiple" indentions. It seems plausible to me that some variation of one of these multi-pattern Vicker's Automated hardness testers might likely be able to create the zigzag patterns on the Busse blades.
Vickers hardness Test .