Some of you may already know this but I just discovered today that the checkered (81-158 & 159)Walnut grips are serial numbered to the reel they are installed on. Besides the 81-101 part number there is also another stamped number on the 81-101. I discovered that there is a corresponding hand written number on the back of the -158 &-159.
Another way to identify original. All of mine match.