[Mariebl]

Why are they using fish entrails to date something that was firmly recorded by the Romans at the time?

They hid the answer in the next-to-last paragraph--poor article writing on their part. It seems someone found a coin that might have been struck at a slightly later date. (But it's too corroded to be sure.)

[gleeaikin]

I don’t know if records have been found of anyone other than Pliny the Younger recording this date. At any rate, how many people don’t trust scientists and historians? Also, I believe he may have been 18 or 19 at the time. Who trusts young people? So far as the coin was concerned, people later dug down into various of the ruins looking for treasure and family possessions. Not that hard to drop a coin in the process. I clicked the links for the story and for Comment #1, and don’t know what picture is being referred to.