"Did Tactical Squad Markings exist in 30K pre-codex astartes?" I have no idea.. but I bet the fluff nutters do if you ask it as a question on a forumy thingy..
IRRC.. dark angels have just started to stick heraldry and stuff about caliban on their stuff during istvaan time frame but hardcore loyalists see regional heraldry as near treasonous..
Lovely models, nice paint.