I have 2 Guide rails for sale, 1 was mistake I ordered the newer style for M44 type case that does not use the idler sprocket, 2 pics of this one. The long rail that has the tag on it I had lost in boxes of parts in storage and had to finish my motor so I ordered another new one. Then got to clean out storage months later & found the first one I had bought to rebuild a different M42 from 3 years ago.
PM if interested.
Update 1/28/17 , the left side rail has been sold.