Dates like 1960, 1970, and 1982 cents have large and small date varieties. Was this done purposely or accidentally? I can not find this out online.
Here's a nice write up on the 1960 . https://www.pcgs.com/news/small-date-cents-had-a-truly-big-impact
There used to be a website that listed all the design changes, for all US coins, from around 1900 on. But it's defunct now. However, I have a copy of it. If you'd like it, send me a PM with your email address and I'll send it you. That said, all design changes were intentional in a way, other times they were unintentional in another way, and sometimes it was both. Most of the time it was because the master hubs wore out and they simply had to make new ones. And when ya do that, well changes happen, sometimes by design and sometimes by accident. The bottom line isn't why they happened, merely that they did. It's the same kind of thing as it is with grading coins, it doesn't matter how the marks, hairlines, wear, lack of eye appeal got there - it only matters that they ARE there !
1982 it was intentional and necessary because if the metal composition change they had to design thinner and change the pressure used to create a better relief on the coins
In 1960, real hub doubling could occur as the process used at east 2 hubbing squeezes. But it was possible in Denver where they lost tract of the hubs and pressed with one and then annealed and pressed with the other date size and didn't notice, and minted the 1960-D DDO, small date/large date cent. Obviously there were problems as it also has a RPM that was totally separated D's. Jim
I should also mention in 1960, the cent proofs had a sm date/large date, large date /sm date, and a lg/lg/sm date .
All dies were made in Philadelphia until 1996 or 97 when Denver started making thier own from Master hubs provided by Philadelphia. You story line is probably correct but it took place in Philadelphia not Denver.