Well the "mythical" 43D that's worth tens of thousands would have been bronze, not copper, and would be a rareity certainly if a true specimine was actually found. To my satisfaction so far, all 43D's were struck in steel except for the forgeries. I've yet to actually see an actual authentic 43D bronze. The rumor is that there were 40 or so accidentally produced, 12 of which are "claimed" to be in the hands of private collectors, but show me one, please. I'd love to believe.
Silverstreak, if you want to test your pennies yourself as to whether or not they are authentic bronze cents, hold them up to a magnet. If they stick to a magnet, you have a steel coin that's been plated to look like bronze/copper, so don't waste your time going any further with your research. If they won't stick to a magnet, you might have a fortune as long as they aren't a forgery. Take it to a reputable coin dealer. They'll weigh it and perform specific gravity tests on it and check the strike and the tail on the three, and if it's real, you're rich. If they turn out to be real though, please please please post a picture of them here so I can actually see an authentic 43D bronze before I die.