I know - but it's a different one. XIIb - would be a Canadian built IIB? Mk.X is a Mk.I - Mk.XI is a Mk.IIA - Mk.XII is a Mk.IIB (I think). If that's true though, that one in the picture (modern) is a Mk.XI because it has eight .303 cal - which would mean it's IIA (IIB had twelve).