They were made with no mint mark. I am not a Lincoln Cent expert or acolyte. But in my "shower thoughts", perhaps there are collectors that inspect and catalog die combinations. Of course there were 4-5 billion cents made in a year bearing no mint mark. I assume the US Mint would report West Point coins in the Philadelphia column. Probably in the past people are tried to do this, but hey, it's 2021 and we have the technology. If not, then in the future. Are there records of dies being sent to West Point? References: https://www.cointalk.com/threads/trivia-west-point-coin-milestones.42402 http://www.coinpage.com/coin-image-5445.html
After posting I thought, are die varieties (not errors) possible in "modern" coinage. According to NGC, pre-1990 are candidates for varieties. The second area concerns dies in which nearly the entire design was hubbed, leaving only the date and mintmark to be hand punched. Such coins were made from the late 1830s until fairly recently, but since 1990–91 all features of the die have been fully hubbed with almost no variation beyond that caused by the occasional double-hubbed die.
Perhaps the close "AM" cents were minted in West Point. Philadelphia perhaps sent them over dies intended for proofs.
I don't think anyone was able to discern the no mink mark pennies from Phil, West Point and San Francisco from each mint. SF didn't mint pennies for the same years as West Point but did in from 1978-thru 1983. 1974 thru 1985 carried the same reverse RDV-004 from Variety Vista online catalog for the 7 memorial reverses. So, the wide AM variety would not be a option. here is a picture of the mintages for those years if your interested.
Probably, but only numbers of dies sent. No way to relate any of those dies to actual circulation coins. Yes the dies probably had tiny markers that would match markers on the coins, but we don't have the dies so we have no way to know what those markers are.
Philadelphia doesn't carry a mintmark for many reasons, this being one of them, when one of the other mints like W or S has down time and helps out with circulation strikes, there's no way to tell one from the other. so here's no instant rarities or a random low mintage item. Philly also has the engraving and design departments and master hub and master die making capability the other branch mints don't have. In circulation strikes, if Denver, or Sanfran (if they were striking for circulation like they used to) did get a die that was missing the mintmark and used it, it would be assumed it was from Philly anyways and be no added value, the only way you'd be able to tell the mintmark was missing would be on a proof strike and knowing it should have an S on there for where it was made. for cents, Philadelphia lets say, they made 3,542,800,000 cents in 2019. the die pair strikes about 12 coins a second per machine, 720 coins a minute, 43,200 cents an hour, and they change dies ever 6 hours approximately around 260,000 strikes. at that rate it would take around 13,600 die pairs for the annual circulation production of Philadelphia alone as an average, if all those conditions are met and rates and times are followed. I don't know for sure, and there's always variables, but it's safe to assume the number of dies per mint each year is A LOT and a lot to catalog, and then do this also for Denver, and then I guess, exclude all those dies, and pairings, and be left with possible "West Point or San Fran" strikes? It's an impossible task really for just one year, certainly impossible to do it every year, especially considering the Date and mintmarks are now on the master hubs so there's even less variation, and each mint gets their master dies from Philly ready to rock and roll to produce hubs and then working dies.
I think you're confused. RPMs have been impossible since 1990 because the mint marks are no longer punched by hand, but die varieties (whether intentional design changes, accidental proof obverse/reverses, transitional varieties, doubled dies, etc.) are still completely possible. Doubled dies made 1997-present will look a little different from older doubled dies because the mint switched to only using single squeeze hubbing that year rather than multiple rounds of hubbing and annealing to produce dies, but many classes of doubled die (especially VIII/IX) are still possible.
John's estimate is a little high as they don't change dies that often. Average die life for cents is a million to a million and a half. So the number of die pairs is probably closer to 3000 die pairs or so. Still way too high to catalog all of them
This is a cool discovery/realization if true. I'm sure there are experts that world concour or just say there is no 100% way to be sure. On a similar subject, I'm sure some people are ecstatic that Denver put a mintmark on the 1916 dime; And most people wish there was no mint mark If only there was a law that mandated that coins bear the mint mark from where they were made. How different coin collecting would have become.
