Possible einsatzgruppe A feldpost (?)

[ZeraAmalek]

Good day, by looking at this latvian volunteer's feldpost envelope, dated to 1943, I have realized that the feldpostnummer on the envelope may indicate that the man belonged to the einsatzkommand 2 of the sicherheitsdienst (SD). The issue is that the cancelation date on the envelope does not match any date which matched this specific number.

What do you think?

[BlackCat1982]

Not sure the feldpostnummer isn’t 33988, it’s not easy to see from the photo.