Is there an option to import Unreal Script files (made in UE 3) to UE 4, or is there any tool that can convert .uc files into something I can import to UE 4?
Nope, UE3 and UE4 are too different anyway, that would not make any sense. For example, SkeletalMeshComponent do not have the same methods/properties, same with pretty much everything else. In UE4 it’s all about C++ if you want to code, or Blueprint if you prefer visual scripting.