US #606 Line Pair - Guide Lines, Dots, And Scratches

Below are several #606 line pairs which might interest the fly spec folks. Two have positioning lines/dots and the first one has what I think might be a scratched plate. Opinions/input/sharing of knowledge appreciated...
don

hi Don. Great pictures! I am one of those fly specking folks, although I do not categorize your examples under fly-specks! I think they are downright varieties. The one you marked as a scratch is in my opinion also an LOM, a layout marking. In modern stamps a good source for LOM's are the stamps printed by the Cottrell presses and in particular the first 17 issues of the Transportation Series. LOM dots and -lines have been located on samples of almost every plate!

Peter