The ground gear from Gamma Task Force that i bought on my Jem'Hadar is Mk XII. It only showed as Mk XIII in the projects list after reaching tier VI. I didn't buy the Space set until after reaching Tier VI so can't comment on if those are Mk XII before Tier VI.
Similarly, the space gear and weapons from Discovery Legends i bought on my Discovery captain is Mk XII, also only showing up as Mk XIII in the projects list after reaching Tier VI. The Discovery Legends ground gear i bought is Mk XIII though. The Omega Force rep ground gear on my Discovery captain is also Mk XII instead of Mk XIII.