I emailed concierge team this morning and this is the reply i received:
We do continually review our offerings and have discontinued the ability
to drop items off at Guest Services to be signed. We have added more
character meet and greet experiences onboard and encourage all guests to
bring their items along to have signed when meeting our characters
onboard.
I'm bringing my kids pillow cases and autograph books to be signed. Sorry if you are the guests behind be..I'm going to make sure my personalized pillow cases will be signed since it was kind of pricey and wanted to make it special for the kiddos. Never know when we will return