Well, I´m a spanish bartender and "cubata" was a way to call any distilled-coke combination.
Cuba libre it´s used just for Bacardi- coke and how Santi G. Lucchi says RAF it´s for gin-coke.
Here in Spain when ordering a "cubata" they refer to a slight variation of the Cuba Libre cocktail but without the lime, just a rum & coke. Here, the more elderly people call a Gin & Coke a RAF (Royal Air Force) since it was the preferred drink of some Englishmen belonging to said Force. But the name's been forgotten by the newer generations.
Cuba libre it´s used just for Bacardi- coke and how Santi G. Lucchi says RAF it´s for gin-coke.