Any significance to the pa color on swedish m/39?

Much of the m/39 I get to see is from the late 1944-1945 period and of course later contract buys from Sweden for our M/49 SMG’s. laquered pa/neck seal are usually reddish-purple on 1940s 9 mm, but this Karlsborg 1954 vintage has a green pa/neck color.
Btw: does anybody know when the swedes changed to non-corrosive primers on their 9 mm?

The Ammunitions register of 1964 (I only have a U.S. Translation) mentions m/39 having lilac and m/39B having red “sealing varnish”. Green is not mentioned in this 1964 document.

The earliest Swedish 9 mm Para from around 1941 didn’t have a colored seal. Then came the violet (lilac) seals, which it seems in the 50s and 60s were changed to green (I have heard it described as blue, because sometimes it is very thick and dark, and looks almost blue, but I am sure it is green), and then to red. I am not sure that all red-seal ammunition is M39B, but all M39B ammo is with a red primer seal. I have been told that the early colors were corrosive primed, and that red also indicated a non-corrosive primer. I don’t know for certain if that is true, but it seems likely.

My earliest red-sealed primer 9 mm from Sweden is from “26” (Svenska Metallverken) and is dated 59. I have one from “27” (Norma) dated 60. I don’t save dates, so these will only be approximate to when they changed. There is one anomaly among them. I have a “26” cartridge in case dated 45, but it has the commercial “SM” stamped primer cup and I understand it represents the first Svenska Metallverken COMMERCIAL loading of the 9 mm Para cartridge. Again, I don’t know if that is true. It is certainly from SM however, as case manufacturer and primer cup marking match. It has red primer and neck seal and what appears in color and tone to be a plain-steel (not chromed or nickeled, etc.) bullet jacket. At least, the bullet is highly magnetic, even at the very tip, which says “steel jacket” to me. In this instance, the red seal may be because their commercial ammo with “SM” primer was non-corrosive, if that is true.