Unusual markings on 2" mortar tail

[BMG50]

A friend found this recently dug a Mazak 2 inch tail dated 1942 not only with the usual red paint marking on the tail fin but two green paint markings as well . Anyone know what green on the tail fin denotes or seen this in and DWS notes etc. Remember this has been in the ground for 80 years so not some recent add on.

 

[ron3350]

None of my Mazak tails have any green paint on them and no green paint over-runs on my smoke ones either so I cannot help.

 

[BMG50]

These are not over runs. Could be marked on the tail to identify some sort of experiment or trials??. The tail wasnt attached to anything plus the small tail grub screw is turned out, so its been taken off something. No cartridge was found inside the tail either.