I friend asked me to find out about his inherited 52-1 with a frame weight. No markings or stamp on it. But, it looks like the original type except it has a round rod about 2 inches long that can be extended forward from the front of the weight. The metal rod has a round plastic insert that is adjustable forward for the counter balance you want by moving it out of the weight forward of the frame. Very good idea to find correct balance. Even if not original I would like to get any info about it if possible. Thanks Richard