Singer TV6U-Curious why these colored markings

[AiboPet]

I am recapping another of my little Singer TV6U "sweeps" boards....just to see if a casual "complete" recapping will yield better results than the other "one-by-one" board I did a few days ago.

I noticed that ALMOST all the electrolytics have been marked on top either red...or green. ALL the same board have these markings. They are completely filled in on top of the cap in like red or green "Sharpie" style marker. There are only a couple on this board that are just left silver on top.

Without looking where EACH one of these are in the Sams (in the schematics) and guessing if these colors mean anything, is there some sort of code to this??

Is this some way of saying "vertical" or "horizontal" sections?

I did notice most of the differences in vertical were "green" marked caps, and at least the one smaller cap I changed out that made a big difference in Horiz hold...was marked red. Was this just coincidence?

I don't see anything in the SAMS that mentions the "marker" colors on top of the electrolytics. Some of the green mylars are also marked red on top as well...but in a touch of red paint.

I'm hoping to save some grief if these may be horizontal and vertical identifications. I figure if I changed all the green marked ones at once, that maybe I could concentrate on the linearity/size issues....BEFORE tackling a horizontal issue? If there IS some rhyme or reason to this, I guess it would be wise to mark the replacement caps with a red or green Sharpie on top as well?