This page shows 3's from various years of cents. Note the 3 on the 1943 cent which is distinct from the other 2. If you have a 1943 copper cent, the 3 should look exactly like the one in the picture above.. If it looks like the 3 in the 1933 cent, then it is probably modified from a 1948 cent. If you study the 1953 cent closely, you'll notice that the top loop of the 3 is smaller than it is on the 1943 and the bottom loop is larger and more ovular. Note also that the right side of the 3 is almost straight up and down whereas on the 1943 the lower loop sticks out. In short, the 3 on a 1943 cent is very distinctive.