All coin dealers get calls about the 1943 copper penny. Lots of fakes are still in circulation, and in collections. Once a year or so a radio station gets lots of people excited about finding this penny. The internet is good at showing big dollar numbers of what it could be worth. It is VERY unlikely that you have one.
1943 copper alloy cent is one of the most idealized and potentially one of the most sought-after items in American numismatics. Nearly all circulating pennies at that time were struck in zinc coated steel because copper and nickel were needed for the war. Approximately 40 -1943 copper alloy cents are known to remain in existence. Coin experts speculate that they were struck by accident when copper alloy 1 cent blanks remained in the press hopper when production began on the new steel pennies.
Because of its collector value, the 1943 copper cent has been counterfeited by coating steel cents with copper or by altering the dates of 1945, 1948, and 1949 pennies.
The easiest way to determine if a 1943 cent is made of steel, and not copper, is to use a magnet. If it sticks to the magnet, it is not copper. If it does not stick, the coin might be of copper and should be authenticated by an expert. It will need to be graded / confirmed real by NGC or PCGS to be worth anything more than a few cents.