I think you might be right about them being DDD. The overly large AK inclines me to that conclusion. As they are recognisably anthropomorphic, I think we can rule out Stan Johansen as the culprit. They certainly don’t look any other in production lines of insurgents that I can think of. Not Empress or TAG or Mongrel etc.
Getting back to your need for standing gunners. Eureka have both Somali and Zanla crew figures for their DshKm that are useful for conversion purposes. There are also some standing WW2 US army .50 cal figures available from Company B that might help.