Well we know where he got it from, Nadia. Great to see her back, and my god that girl is well traveled, she seems to turn up everywhere. I was wondering about timelines, I think Sayid went to London for a spell, right? So was he on Nadia's trail, but she'd since left to America at this point (where she'd then meet Locke).
Confusing stuff, but minus Christian Shephard it makes her probably the most appearing flashback character, so far in Sayid's life, Locke's and Charlie's.
Side note, all Charlie's flashbacks seemed to have a water theme going on I notice apart from the Claire one (possibly in reference to his realtime mission?). The van in the rain, the pool, a drink with Liam, Nadia in the rain - maybe its no big deal but a nice little thing.