CONGRATULATIONS on booking! I just officially booked yesterday and I am going to be a Sandals bride, as well! Originally, we wanted to get married at the Sandals Grande St. Lucian, but discovered it would be more financially "do-able" for us and our guests to go with the Sandals Grande Ocho Rios resort in Jamaica, and then do a short MiniMoon just the two of us at Sandals Royal Caribbean -- we're thrilled!
And yes, I also have been told by my TA that if Sandals runs a special (and offers a better price on your room than was offered at the time that you originally booked) that they are happy to ensure you get the best deal. Now THAT is customer service!
And, YouTube has some great videos of ALL the various Sandals resorts -- definitely a resource worth checking out! It will make you feel like you already "know" your resort before you even get there!
Best wishes to you and your FI -- your wedding is SUPER CLOSE! You must be bursting with excitement!