My understanding is the main visit to the Archives at issue (and there are several) was in October.
However, I don't believe the FBI came on the scene until January. That is not "last fall". And notice Lanny Breuer's deceitful "this was a year ago" spin he tried to haul out today.
Beware of defense and dem representations of the timeline.
And they were likely trying to see who Berger was going to pass the classified to. Looking for his handler. They would treat it as a espionage investigation.