DCL's policy up until now has been that your pricing is locked in as of the day you book. I've taken advantage of this on several occasions. I saw a response to another post where someone indicated that they had confirmed with a CM that this policy hasn't changed.
I'm just wondering how much that actually matters in this case, except for those who booked on opening day for Platinum CC members. The fares jumped quite a bit in some cases from Platinum day to Gold day and then the cruises sold out. Prices usually go up as more and more people book, but very few people have been able to book since late on Gold booking day. It would be interesting to see prices for the categories that are now popping up on the web site from time to time.
All that said, I agree with the PP who said that it's probably best to go ahead and book and try to upgrade later.