Yeah, Picard simply says he did what any good helmsman would have done, but Riker seems to think Picard is being overly modest in this regard. Picard says that he "did what any good helmsman would have done" but he says this as a man who's served as a helmsman, since in the flashbacks we do see him in the Captain's chair.
Memory Alpha (a Wiki based of "canon" Star Trek works) has Picard taking command of the ship, Jack Crusher dying on an away mission, the ship operating in the Cardassian Wars and then the Battle at Maxia. Taking place over the course of twenty-some years.
While the dates are assumed, we're told enough over the course of the series about Picard's time on the Stargazer to know he served on it for quite some time and it's clear to me that the incident where Picard took command, prompting him to be given command, is different than the incident where Picard lost the Stargazer.
As for what became of the Stargazer between the battle with the Ferengi and "The Battle"? Canonically we have no idea, "The Buried Age" by our very own Christopher
covers this very nicely. in the book the ship was overly contaminated by radiation when the crew evacuated and the auto-destruct system failed. (Not really spoilers of the book since the incident on the Stargazer is a fairly small part. It can be assumed the Ferengi performed radiation clean-up of the ship before returning it to Picard.)
It's "maybe" possible to just believe the technology on the ship was old/already leaked to other races and the ship contained no sensitive information or technology to make Starfleet overly worried about it. Or maybe they *had* been looking for the ship but were never able to recover it.