Series III
4897 - 4906 (10) delivered Jan 41 - May 41 (SAI Ambrosini)
5201 - 5260 (60) delivered Nov 40 - Dec 40 (Breda)
6795 - 6804 (10) delivered Jun 40 - Jul 40 (Macchi)
6829 - 6890 (62) delivered Jul 40 - Dec 40 (Macchi) Series VII
7659 - 7708 (50) delivered May 41 - Sep 41 (Macchi)
two opening side panels replacing the sliding canopy
roll bar-equipped dorsal fairing replacing the aft glazing
mass-balanced rudder
fixed-type tailwheel and bay covering
83-litre internal fuel tank under new dorsal fairing
new radio
external antenna
different wing-mounted pitot tubes
These changes came after the first ten Series III. So the remaining Series III and Series VII are essentially the same. As far as I can tell.