Some times things are just a mystery.
I normally get the RSSC brand of sparkling in the bucket on most sailings (never happened on the Song or some Diamond).
Last year on PIP Sheri and I got the Godiva truffles, a bottle of Veuve Cliquot, AND daily hors d'oeuvres (we were in the cheap seats). Why? My guess is that it was Sheri's third time on the PG and I had the most past passenger nights that sailing.
To answer the original question, I do not think you can exchange the bottle of RSSC bubbly, just the "normal" in room set-up. I view the bubbly as an extra perk.