That was a 1974 D aluminum cent, a coin that never should have existed in the first place. They do experiments like that aluminum cent in Philadelphia, and the 1974 plain aluminum cents were most likely part of the test run of something like 1.5 million pieces they did to make sure they would scale up to regular production. There would never have been any good reason to have a few (or one) struck at Denver. I would find it difficult to believe there was ever any official order to have that coin struck. I think it was something the Denver Mint official did on his own.
And the six figure sum was what they expected it to bring at auction, the proceeds of which were to be donated to charity. When it was publicly announced the government claimed if was their property and the auction company withdrew it and returned it tot he consignor. The government kept claiming it was theirs and that it should be surrendered, but in that case they also never actually made any attempt to physically recover it. The owner finally turned it over to them to make them go away and leave him alone. I believe he had to get it to them as well, they didn't come to get it.