Bobbi, when we were on Rhapsody in 2000, our balcony stateroom had robes.However, we found out from our tablemates (in an ocean-view cabin) no robes. They were on their honeymoon, so I ended up loaning her my silk one that I had drycleaned for the trip. :-)
I would think, though, that you could perhaps ask the cabin steward for one, but that would be a crap shoot if you got one.
Hope that helps,