Good point! I think they have two colors because they have two efferent types of missiles: anti-missile & anti-aircraft. I don't think its a camouflage.
here are some rare pictures of historic SSM Systems - meanwhile all of them seems to be retired from active service
Marcel Dassault MD-620 = Jericho 1
manufacturing of the first missiles at the Dassault plant in Martignas-sur-Jalle
missile tests at Ile du Levant
MGM-52 Lance
SSM "Luz"
290mm MLRS
A test of the Gimel-52 Missile (prototype of the Luz Missile which was the prototype of the Gabriel anti-ship Missile) from 1963. The film features then Prime Minister/Minister of Defense David Ben-Gurion, Shimon Peres (Deputy Defense Minister at the time) and Tzvi Tzur (Chief of Staff).
During this week, the Kfir Brigade 93rd Haruv Battalion completed a drill in the Jordan Valley. During the drill, the Brigade's soldiers put both their urban and open-field warfare to the test.