[AdmSmith]

Yes, they are part of the Russian alphabet soup, not a private contractor, just ordinary Russian deza.

[AdmSmith]

Wagner PMC is a secret detachment of Russia's General Staff of Armed Forces – confirmed by mercenaries’ ID papers, says SBU Head Vasyl Hrytsak.

GRU made a similar mistake with the passports as for the operators in the Salisbury novichok attack:

Just run the passport numbers 65 39544 NN, NN= 00,01 - 99 to find the usual suspects.
more here and another number series:
https://ssu.gov.ua/en/news/1/category/21/view/5632