I believe not, the usual stealth roll is for a weapons lock. Merely to scan it, is, well to scan it, although if you then chose to fire, you would still need to beat stealth. I suppose a real world explanation could be, as a Pilot on a strafing run, you can easily see your target, but then when you come to fire, you are looking at stability, windspeed, evasive maneuvres etc.
likewise, your scanners or your eyes can see the stealthed ship, but your weapons just can't get the data they need to compenaste for relative velocity and suchlike.