Hello,
I just read on an italian site :
"The plane carried two bomb throwers hanging from the lower wings and they were used in colonial operations (Libya, Ethiopia), while in Italy, they were not installed as the Ro.1 was used as an observation aircraft. There was a camshaft which, by rotating, dropped the twelve 12 kg bombs. Normally in war operations the plane armed only one rack."
No explanations about the dark panels on the sides of the fuselage
At this address : Romeo Ro.1 | Drive&Fly Model Club Modena they should be able to give you more details. Best