That's not an early stock as it is not the right style. The model 60 came out around 1939 and the op said his dad bought it in the 1950's, long after the model 60 was introduced. Before the model 60, it was just called the Cooey Repeater. They had a finger channel but it ran the full length of the forearm. Plus the pistol grip was different as was the whole dimensional configuration of the stock.