I worked at SF mint in late 80’s where I heard the story of…

I worked at SF mint in late 80’s where I heard the story of the 43 copper pennies made in 42 before the order to change them . I also saw a crate of them they could no longer use because of the change. Here is my question. I have 43’s I know are cover ups down by all the mints because tons of copper was wasted at a time of war. They had to hide it. If a penny is stamped over but you can make out the cover up of the number. Does the underlying date count? They have the marks of the 43 c