Don't try and over think origins or what nationality may have produced the cut in one way or another.
It's a simple basic engravers cut going back to forever and was used on everything.
Engraving is a very personal challenge and trade. You accomplish things by finding a way to get a final result that is acceptable to the market and customers.
Flat graver powered by a chasing hammer is probably the common method. A flat not much wider than the height of the 'nick' usually work best if for nothing more than not cutting one too high. But really, as long as the flat is wide enough to give you the correct height it'll do.
Some people cut a border line first and let the tipped on it's edge flat ride that border,,tipping the flat over on a nicely timed cadence of hammer taps. That leaves an evenly spaced pattern as well as the tool travels from one cut to the other.
The taps vary in power as the flat enters and exits the cut so as to leave a clean triangle appearing chip w/o a ragged forward edge. Takes some practice. Try both 'sides' of the cut,,one may be more comfortable than the other for you.
By sides I mean rolling the tool forward to make the cut (nick is above the border on the work),,or rolling the tool back towards you to make the cut (nick is below the border on the work).
Just turn the work around in the vise to place it in the position where it's most comfort to cut.
Some don't bother with the border line cut. Prefering to use only a lightly scribed guide line instead. The same technique is used but the flat traveling from cut to cut leaves a very light line instead and many prefer it to the heavier border. I usually do the border this way.
The nick can be cut with a 'graver (by hand power) and is very often. It's not all that troubling to do in brass, silver, ect and even in steel if the size is kept reasonable, it's surprising how much material can be removed. Extreme depth is not necessarily needed,,just uniformity.
Some using this method make two separate opposing cuts for each nick. One clean 1/2 of the triangle from each side meeting in the middle. Sort of like chip carving I guess.
Very elegant looking especially on silver,gold, ect and when the tool is highly polished leaving the cut surface equally done.
Again, most just go about it spacing by eye. But I've known some that laboriously (it seems) layout the cuts first and then cut. I certainly can't fault their work and as I said up front,,it is their way of getting the desired result.
Another way is cutting the nick from outside the border with a V tool, perpendicular to it and ending with the base of the cut at the border. I've seen that occasionaly on some Parker shotguns. Who knows who cut them. It's just another way of doing the job.
The dot of the nick & dot is usually done afterwards with a small V or even the same flat that the nick portion was cut. With or w/o a guideline,,go back down the line of cuts and pull a tiny chip out betw each one. Keeping them equal in size and visually equal in distance from the baseline is important for the final look.
I used to use a flat graver for this cut, ,in fact long ago I used to use a flat for most all my cutting by the same method,,tipping it up on one of it's points to cut a line. I could make thin or thick lines by mearly laying the tool over a little as I cut. My very early way of tackling my inability to properly sharpen a V tool.
It's still not a bad way for the occasional engraver to get at it.
Now I use the V tool (finally learned to sharpen one right!) to cut lines.
I use the same V tool to cut the nick & dot border. One side of a V tool is a flat graver edge after all.
It works for me,,it may or may not for you.
I'm surely not the first to do this but the point is that most anything and everything has been done in the trade to get results.
Early apprentices may have been beaten into submission to do things a certain way, but freedom of their own ways and techniques takes over once they're on their own no matter where they are.
Just my thoughts.