I have found 4 1983 pennies so far and the top two in picture Im sure are copper plated Zinc. The bottom two however are different. Has a metal ring sound when dropped and color is different. I have not weighed them yet... Thoughts on these please. Image on right is one that sold at auction
You must weigh it first. It's almost 100% going to be zinc. Usually you can tell by appearance that there are some zinc spots or other markers.