Besides what Matthew_Baker already mentioned, false visors became part of the standarized factory camouflage scheme. Especially Škoda used very uniform templates until the end of the production at Plzeň. BMM camo pattern was a bit more random, even the placement of two false visors differed, diagonally to the right under the visor vs. Škoda's style which ran both left and right.
This picture shows the differences between with these two manufacturers, as you can see Škoda's patterns are identical (BMM is the 2nd from the front)
If you are interested in more examples, then I'd highly recommend "In Focus 1: Jagdpanzer 38" by Lee Archer, Felipe Rodna