These and similar Roman coins found scattered around North America are generally considered legitimate, in the sense that they are actual Roman coins and not forgeries, but they aren't regarded by archaeologists as evidence for Pre-Columbian contact between North America Rome. Back in 1980, Jeremiah Epstein et al examined 40 known examples of Roman coins found in North America, including the ones referenced here. They concluded that they're most likely either misplaced from collectors or deliberate hoaxes. There was a huge boom in the number of Roman coins in the hands of US collectors following WW2 as soldiers returned from the war, and all the discovers of such coins in the US are clustered after this point. The coins aren't found in a contemporaneous archaeological context; we don't find Roman coins in Hopewell burials, for example, despite the Hopewells' love for using exotic items from all over North America as grave goods. They're also found all scattered all over the US, with no consistent pattern indicating a logical spread of Roman contact in the region or supporting archaeological data from such a widespread interaction with wayward Romans. They're not, for example, more abundant on the coast and thinning out as you go inland (if anything, they're more common inland than on the coast), and - going back to the lack of any archaeological context - there's nothing to indicate that they were moved by indigenous trade routes. There's also a decided lack of any additional Roman artifacts, like weaponry or amphorae, that would corroborate the coins.

In contrast, when Europeans show up post-Columbus, we see a clear pattern of European goods moving inland. There's a significant variety of items, including Spanish swords, chain mail, beads, bells, glass, seeds from Old World crops, etc., that start showing up in Native settlements in the region. If there were a Roman presence significant enough to scatter coins over such a wide area of North America, we'd expect to see a similar pattern.