Yeah there is. Legolas was Thranduil's son. Thranduil was Sindarin, Gondolin was filled with a bunch of Noldor. Legolas of Gondolin is not Legolas of Mirkwood. It's like the Jimmy that sits next to you in English isn't the same as the Jimmy that sits next to you in Physics. Though I do realize that Elves didn't use the same name twice. Tolkien messed up about that.