Those are all large. Copper is 3.1 and zinc is 2.5 grams. There has only been 1 1982-D small date copper found so far out of 17 billion 1982 cents, good luck with the search.
They didn't intentionally mint 1982-D small date copper cents, and I thought only 1 had surfaced. If I am wrong, etc. Link: http://www.numismaticnews.net/article/rare-1982-d-small-date-copper-found
The easiest ways to tell large dates from small are that; 1) The 2 looks like a swan in the large date, 2) The date is much further away from the rim. Another "sure fire" way is to get a known Large Date and a known Small Date and use those two coins as your references.
Can you independently confirm this? Unfortunately, I could find little that suggests this to be the case, and in fact, as recent as last summer the discovery coin was still being labeled as "unique", so I'm having a very hard time buying the idea that they've been "popping up like flies".