Automatic Advance Unit - 4CA vs 6CA

[hoogerbooger]

Rupert says cam is taller on 6CA, than 4CA. Anyone got a spare 4CA and or 6CA AAU at hand and can measure the cam height?

googling,it looks possible that the cam section itself may not be taller but there is a bigger gap below the cam section to the plate ?

picture of a spare I have attached, showing measurement. trying to work out if it is 4CA. ( my measurement is from the top of the plate that the springs attach to)