Would that be one with numbers starting in 6.
The 12th were formed in July 43 and were a fully fledged Pz Div. It had a full pz Regt with 2 battalions, the 1st with panthers, the 2nd with Pz IV's. It is possible that the 2 battalions had different coloured numbers. The colour plates I have seen show red numbers on the panthers and I think this is one of those cases were you have to make a best guess as it would be hard to prove either way.
If it was me, I would go red.
I am a Norfolk man and i glory in being so
On the bench: Airfix 1/72nd Harrier GR.3/Fujimi 1/72nd Ju 87D-3