How do you know if you have a copper 1943 cent?

No additional authenticated 1943 cents have turned up in the last 25 years or so.

A genuine 1943 copper cent:

> will not stick to a magnet.

> has a date where the bottom loop of the "3" is elongated rather than circular

> weighs 3.11 gm

> has smooth metal on the flat surfaces of the coin.

If it appears to be copper but sticks to a magnet it's a regular steel cent that has been plated.

If the bottom loop of the 3 is round, it's a 1948 cent that has been altered to make a crude counterfeit.

If the flat parts of the design are somewhat pitted you have a copy, again a counterfeit.

If it weighs much more or less than 3.11 gm it's also a fake.

If it passes all of these tests you should have it examined in person.
If you mean a 1943 Lincoln cent struck on a copper planchet, authentic coins are valued at $50,000.00 or more.