Tom Paris appears in Barclay's holodeck program as a Lieutenant (Junior Grade), as that was his rank as of season 4's "Message In A Bottle".
Barclay would have had no knowledge of Paris's demotion to Ensign in season 5's
"Thirty Days".
At the end of the episode, nobody on Voyager (even the Doctor) seems to know or remember Barclay, although he appeared before
in the Season 2 episode, "Projections".
In the scene where Barclay talks to Admiral Paris in the Admiral's office, a long shot shows a reversed picture of Tom Paris with a combadge on the right side of his chest.
A few seconds later, a close-up shows the same picture in it's correct orientation (combadge on the left side of his chest). This picture is from "Star Trek: The Next Generation" episode "The First Duty".
Only knowing that they had assumed certain roles within the Voyager crew, and nothing more, Barclay had the Maquis crew members dressed
in Maquis-style clothing instead of Starfleet uniforms.