1970's Hamilton Chronograph

Here is a Chronograph I picked up on ebay. I believe this is the 1970's Chronograph with a Valjoux #7734 movement inside. With the sub seconds dial at the 9 o'clock position, 30min counter at the 3 o'clock position, and the date at the 6 o'clock position. 17 jewel manual wind movement labeled Hamilton 644 is looking good.There were numerous black marks on the dial on the periphery at the 3, 6, and 9 o'clock positions, and even a lume stain under the H in the Hamilton emblem. I really like th