If you booked an inside room, you are most likely to get an inside room, but it will probably be the best category of inside room, which just basically means a higher deck, since you are booked a year in advance. However, there is always a slight chance that you may get upgraded to an oceanview. It really depends on how popular the cruise is. Just remember that all past Princess passengers are supposed to be automatically upgraded in category and all three times I have sailed on the Grand Princess close to 80 percent of the passengers are Princess circle members.
And as an example that it can happen, I was upgraded on my Alaskan cruise in 2000 from an inside on Deck 4 next to the laundry room to a balcony on Aloha deck. I was also upgraded from an inside to an oceanview across the hall on my Caribean cruise with Celebrity. So 2 out of 7 cruises is a good average.