Grey market JLC?

My friend wants to buy her fiance a JLC Master Ultra Thin Moon as a wedding gift. [The wedding is in 5 weeks.] They are not into watches so the notion of chasing a nice second hand one probably is not in the discussion, even if the economics seem illogical based on asking prices that I see online today.

Is there a substantive difference in terms of warranty issues between buying at an AD vs. grey market? Does anyone have a good grey market dealer to recommend that would likely have the watch? Does anyone know what a reasonable discount to dealer price would be?

Anything else I should be thinking of?

Thanks all.