I have just purchased a parallel marking gauge, the metal working style.
It appears to be neatly done and should be quite sturdy but accurate.
But Sadly there is no vernier on this model, so only a mm reading.
So I decided to make this addition. quickly went to my CAD software :
Then printed out the little stamp and, after cleaning up the surface with alcohol, stuck it on the metal.
I then protected the paper with a few drops of CA glue. (adds a little magnifying effect)
And here we go !
Here is a pdf of the vernier, if could be useful to someone.