I recently acquired these model 28,s in a trade. The top is a 6 inch Mod-28 S190xxx. The gun is in great shape but the original grips were replaced with target grips. The bottom one came with its original box etc. The gun has been refinished and has a target trigger and hammer. It's serial number is N202xxx. What would the correct grips be for the 6 inch gun? Any help is appreciated.