Probably not. Ronald D. Moore says that he wasn't consciously trying to connect the episodes together (by using the name Bellerephon for Bashir's ship). That presumably also goes for intentionally dropping in a reference to a spy mentioned in that same episode.
More likely is that Starfleet have several high-ranking spies in the Romulan command, just as the Romulans have at several high-ranking spies of their own in Starfleet Command.
Moore blames the British for his inspiration, though. “The Bellerophon was a ship on which Lord Nelson sailed,” he says. “That’s where I plucked the name from.” Interestingly, the mythic character of Bellerophon rode the winged horse Pegasus, which happens to be another name that Moore used for a starship, this one in The Next Generation episode of the same name. “Yeah, someone pointed that out to me after the fact, but I wasn't trying to draw a connection between the two,” Moore laughs. Nor was he trying to draw a connection between Pegasus's master and the Chimera, the legendary beast slain by Bellerophon (and coincidentally the name of the preceding episode). “I didn’t even know that,” he admits.
The Deep Space Nine Companion