No it doesn't.
It suggests the effects are illegal i.e run counter to the Law of Armed Conflict and various Humanitarian Laws (which the Syrians may or may not be signatories to).
SCUDs per se are not illegal, what you do with them might be. Those same effects could be produced by an other heavy artillery, armour or air assets not just SCUDs. If you want to declare SCUDs illegal, then there's a whole lot of other military assets and capabilities in the line before them to be declared illegal at the same time.