I think it is the 1943 penny you are talking about...
http://www.virtualology.com/virtualp...ppercents.com/
All circulating pennies at that time were struck in zinc-coated steel because copper was needed for the Allied war effort.
Really all? NO!
About 12 examples are known to have been struck by the Mint, evidently by accident, when copper-alloy 1-cent blanks remained in the press hopper when production began on the new steel pennies.
The highest amount paid for a 1943 copper cent was $112,500 on December 22, 1999. 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, '48 and '49 pennies.