The WRACO stamping indicates that your Winchester firearm was produced by Winchester Repeating Arms Company(WRACO).
If a Winchester was returned to the factory for repair which required replacement to the frame it was common to remove the ser.no. and replace it with the letters WRACO, Winchester Repeating Arms Co., Also, unauthorized parties re-sold guns not under contract with Winchester, when these guns showed up at the factory it was re stamped with WRACO. Starting about 1905 Winchester's leaving the factory would be stamped on the top of the frame and the top of the barrel at the juncture of the frame & barrel with the letters WP inside an oval. If your gun was manufactured BEFORE 1905 AND has the WRACO stamp over the s/n then in all probability it'll have the WP proof mark too. Regards, Marty
This firearm has benn overhauled at the Winchester factory and a different receiver installed. James Friend
On WRACO Rd. just west of old US 27.