The general consensus is that two pairs of dies were used circa 1828 to restrike the American Plantation tokens, resulting in three different die varieties: Newman 4-D, 4-E, and 5-D. Of the three, the 4-D is the rarest and the 5-D is the most common. The 5-D is usually seen with a die crack in the right obverse field; the 4-D and 4-E varieties are unbroken. In theory, originals also exist from these dies, but it is nearly impossible to tell them apart. Breen lists a standard weight of 140 grains (or 50 to the pound) for the Originals and 127.3 grains (or 55 to the pound) for the Restrikes. Unfortunately, the observed weights of known specimens of each tend to overlap, making weight an unreliable means of judging status. According to Bowers, Originals are made of 97.5% tin, while Restrikes are made of pewter (loosely 85-95% tin). I am unaware of any metallurgical surveys of American Plantation Tokens, but such a survey might be helpful.
In 2013, Dennis Wierzba advanced the theory that die alignment could be used to differentiate between Originals and Restrikes of the 4-E variety. Wierzba noted that Originals have the Irish harp between 2 and 3 o'clock, and Restrikes have the Irish harp between 5 and 6 o'clock. Wierzba awaits word from other collectors who will either confirm or debunk his theory. If proven, this would be the first, reliable method for determining the status of these interesting coins.
Sources and/or recommended reading:
"Walter Breen's Complete Encyclopedia of U.S. and Colonial Coins" by Walter Breen
"Whitman Encyclopedia of Colonial and Early American Coins" by Q. David Bowers
Dennis Wierzba, "American Plantation Token 4-E: Two Distinct Reverse Orientations (Original vs. Restrike?)", The C4 Newsletter 21, no. 1 (Spring 2013), 13-14.