Yeah, Lt. Commander Sisko was XO of the Saratoga at Wolf 359. Afterwards, he was assigned to Utopia Planitia to work on the Defiant project.
If Sisko wasn't promoted to commander until he was assigned to DS9, then he was only a commander for three years before being promoted to captain. Would that be enough "time-in-grade" for Starfleet?
Starfleet (in any universe) tends not to pay much attention to time-in-grade requirements...so chances are there aren't any.
I mean, Harry Kim was an Ensign for 7 years and while Geordi went from LTJG to Lieutenant Commander in one while Data (who saved God knows how many people God knows how many times seemed to be stuck at LTCDR.