I’m a big fan of Historical: Reunification War. But there may be an issue here - it lists the DV-6M as an option for the Terran Hegemony, Capellan Confederation, Draconis Combine, and Federated Suns in the random allocation tables on pg. 171. There’s broader availability of the primitive DV-1S, which is fine. But the MUL has production of the -6M starting in 2610, over a decade after the Reunification War.
What and when is the origin of the -6M?