BY mm43: The "runway in sight" call 4 secs prior to the initial contact, would as you suggest, indicate they were not visual immediately before the call.
That may be a bit of an assumption. The Board didn't say that was the first time someone called the runway in sight, nor did they say anything about what was said at minimums. I suspect further analysis of the CVR COULD indicate that the "runway in sight" call was intended to verbalize the reasoning behind not reacting to the EGPWS "Sink Rate" call. It may have been an attempt to clarify that they were now visual and not required (by policy or OPSPEC) to react to the EGPWS as they would in IMC. I'm clearly just speculating, however, it seems the whole group was ASSUMING that the call indicates they had just gone visual, even though this was significantly past the MAP. Just trying to find a way to make sense of the call at that time.