While a similar handworked version would require many hours of labor and could probably be accomplished, the obvious similarity of this photo cup and a much more modern one produced since the machine age is undeniable.
Are we being had here?
The Romans used tool & die sets remarkably similar to ours to produce a lot of "precision" items. Chariot hubs, mass-produced items like braziers and torchieres - surgical instruments are another item that look modern - except they're in bronze instead of steel.
On the other thread, I posted a number of similar unguent jars that appear to be "precision engineered". This alone doesn't convince me we're being had.
But it would NOT be the first time that much later artifacts have contaminated earlier strata - usually through the sinking of a well or other shaft and the dumping of miscellaneous trash once the well is abandoned.
Metallurgy should give us the answer. Artifacts can be dated pretty closely by the composition of the metal.