Sorry 1942 was a split year for the War Nickel, if it had a BIG P or BIG S mint-mark over Monticello it would be. Here is a description of the War Nickel and link to your nickel.
The novelty of the Jefferson Nickel caused most examples to be saved by a curious public during its first few years, and coins of this type did not become a familiar sight in circulation until about 1940. Shortly thereafter, the onset of World War II prompted the rationing of many commodities, certain metals among them. Nickel was highly valued for use in armor plating, and Congress ordered the removal of this metal from the five-cent piece, effective October 8, 1942. From that date, and lasting through the end of 1945, five-cent pieces bore the regular design but were minted from an alloy of copper, silver and manganese. It was anticipated that these emergency coins would be withdrawn from circulation after the war, so a prominent distinguishing feature was added. Coins from all three mints bore very large mintmarks above the dome of Monticello, and the letter ‘P’ was used as a mintmark for the first time on a U. S. coin. These “war nickels” proved quite satisfactory in circulation, and they were not immediately withdrawn. Instead, they remained a familiar sight until the mid-1960s, when rising silver prices caused them to be hoarded for their bullion value.
1942 Nickel 5C MS Jefferson Five Cents | NGC
Still , those are very cool finds, I like the old nickels.
