Smart Marine Commanders, finding themselves thrust back into
history inexplicably should be smart enough, not to try to influence history but to hunker down defensively while they try to figure out how they got there in the first place and why. Any chaplains in the group would also realize that it was during the days of Augustus that Christ was born. A more interesting location for the modern battle group to have appeared would have been Palestine at that time.
The Romans were adaptive, and mathematics was not unknown at the time. Seeing that it was possible that such weapons could be invented, the Roman power brokers and Caesars would have spared no expense at copying such devices. Roman technical might would have leaped frogged two millenia in very short order while its social institutions would remain barbaric and cruel.
The power of flight would also have been discovered as such marine military force units use reconnansance drones, and choppers and some have harrier jet units. The Romans knew about lodestones(magnetism) and seeing how we put magnetism to use in making electricity, the Romans developing electric power would cause Rome to be a nightmare for the entire world as they would be able to break past the Parthians in the east and to intrude into India. Some Roman genius will say...hmmm perhaps we could power our ships with substances made out of “pitch” as well as the new generators powered with this strange “electricity” and thus the Romans will find the New World and press on to China.
Good luck with that. They might have forged guns and cannons far earlier at the least though. For much of the technology though, they'd be able to do little more than a cargo cult.