Either Ducky didn't want to say anything about Shannon, or possible they have simply lost in touch and by the time they re-met when Gibbs joined NIS, he didn't ask him about Shannon...
I mean Ducky is a gentleman, and before internet it wasn't that easy to keep in touch
Either way I loved the episode, and what they did with their first meeting...
And, yes, it was strange to see the office without the ugly orange... Wonder if we're going to get a new painting now that McGee "destroyed" the wall