Maybe, but from my experience (three times Wonder/Magic), teams come on early on the embark day of the first merry time cruise and decorate.
The decorations are not stored on the ship and it's not crew member that do the decorating, with the exception on gingerbread (it's imagineers from land).
We'd go to bed and it would be Halloween/normal and wake up and it's Christmas.
However, at the time, non of those ships were out of PC, they were Galveston/ Miami which might make a difference.
What I'm saying is, there's a chance, just don't have you're heart set on it...