Can't help with colours but heres some info gleaned from Nafziger OOB's, CD Armies of the Second World War and the commando supremo website.
In 1941 132nd Armoured Regiment had 3 battalions of 52 M13/40 3 comanies of 3 x 5 tank platoons. The other 7 were presumably command tanks but I have not found any further info for 1941 but the 1942 organistion has 1 gun tank as company command and 2 gun and 2 radio tanks at Bttln HQ. In game terms I would suggest the following for a Bttln at platoon level;
1 x HQ (command tank)
9 x M13/40
Looks as if you have enough to do 2 understrength M13/40 bttlns (not sure when M15/42 was available from and how it fits in the OOB) probably 2 Bttlns of Bersagrlieri and a SP Arty Bttln.
References to look for are 941IKAA, 941IGAA & 942IQAN at the following link;
http://www.cgsc.edu/carl/nafziger.htm