I mean, there's no question that the ship had a bunch of Science Officers, and one Chief Science Officer analogous to Spock among them. Such a person is directly referenced in "Conspiracy", for example: Riker wants to summon his Science Officer to look at the bug that Quinn brought aboard. The question of whether he was referring to Data or not remains open.
Timo Saloniemi
"It won't like your science officer... it does like you!!!", I always assumed he was referring to Data because it wouldn't be able to take him over.
That was actually always my assumption as well, but it
is open to interpretation. Maybe Quinn just wanted to go ahead and get Riker on their side before working his way down the senior staff, and/or was afraid Riker would come back with a security team rather than a science officer. Or it might have just been good ole fashioned Villain Mustache Twirling. (Quinn was acting rather weird, after all.)