My SA did mention sealing to me before when I got my white lamb e/w. But I didn't take her up on the offer so I can't say how well it works. But for my next light color lamb I definitely will do it for peace of mind.
ITA. And if there is a care booklet with your purse, read it and see if it is mentioned. It should be mentioned.
I always use luvinmybags product before I take the purse for the maiden voyage. Tis better to be safe than sorry. Of course the cream protectant has to be reapplied depending on how often you use the purse. If C seals it, then check to see if it is permanent.