Think the green one you posted my be an offshoot (expansion) of the left and right marks but never have seen this and don't think the suppliers for brakes used that mark
I have a few caliper pictures with what may be marks (most are simple drops or a run of paint) but not enough IMHO to have any more than a single example each year.
One I have described as a C8O caliper was a spray painted red area but have never seen this on any other original 68 with disc. And without some pattern I would not reproduce it - just me