What exactly should I be looking for? 1970 and earlier, right? Anything else I should be looking out for? Thanks
Look for any "Not Intended for Ciculation" or NIFC halves. These are I believe halves from 1970, 1987 and anything after 2001. Look for proofs or any older clad halves in Mint BU condition (especially 1982 and 1983). It is nice to look for 40% halves from the mid-late 1960s and anything from 1964 or earlier as well.
Why would the OP need to bother reading the twenty-seven post FAQ when I specifically said what to look for in post #2?
My view is: If you don't know what to look for, you shouldn't be looking. Look for whatever you want. Keep what you are searching for, throw the rest back. If you aren't looking for proofs, then somebody who is will eventually find them. Some folks look for No FG, I don't. It's a matter of preference.