These two buildings were used by the US Navy for recreational purpose, at least from the 1960s on. There used to be a sign directing visitors to this hotel and restaurant. Later under Philippine management they were used for the same purpose (Karl believes so).
In our forum we have a page that claims that these buildings were used by the State Department and the CIA in the 1950s. This is the URL it also shows a nice picture of the hotel and not so nice pictures of the swimming pool:
http://corregidor.proboards.com/thread/1171/grande-island