Amazing how well a scabbard will protect the blades from rusting over such a long period of time, isn't it? Always nice to have the numbers matching. I would recommend rubbing down the surface rust with a good gun oil and rag, or maybe even clean it a little 1st with some wadding polish or "flitz". Doesn't really take much to kill the active rust and protect it for the future.
Nice one buddy.
Nice matching s84/98 good oil wipe down as Jim P says and you are set. timothy
good preserve one, most real a d range.