Coin Boy, have fun with those Lincolns, I know I did.
The early ones (copper) weigh 3.11 grams and the later ones (copper-plated zinc) weigh 2.5 grams.
Do you access to a set of scales to weigh them?
If not you can make a crude one by balancing a ruler across a pencil, making sure that it is central.
Put an early coin (before 1982) on one end and you 1982 on the other (make sure they are the same distance from the end)
if they remained balance then you have a 3.11 gram coin, if the early coin goes down and the other coin goes up, then you have a 2.5 gram coin.
It's a bit rough, but it works. To help eliminate errors, use coins with equal amount of wear.