I doubt there are any Buru babirusa in zoos. Several zoos have labelled theirs a such but this is due to the nomenclatural/taxonomic change and the zoos in question jumping to the wrong conclusion.....
I'd agree - Buru Babirusa is the species that retained the pre-split name (which was still 'correct' when the captive population was established), so unless there's strong evidence otherwise then I'd presume these are B. celebensis that are just still being labelled as B. babyrussa.