Buster,
I honestly don't know. The fellow I got it from said he had several "knowledgeable" folks look at it and tell him it was the original bluing, and I know him well enough to believe he wasn't jerking me around. It doesn't look like an obvious refinish to me, but I don't claim any expertise in that area. I also don't know what happened on the right sideplate to the finish, it's smooth, just discolored.