There are three versions of the Voos style etched, 2 of which are on Unmarked blades and the third on maker marked blades. I believe all three were etched by Voos.
The first difference is that the marked blade etch on the marked side is shorter while the Unmarked blades have a longer etch since they need no room for the maker mark.
These two versions differ in the detail of the etch closest to the tip.