Supposedly, the dinosaur king dub keeps some Japanese OST, but I've never been able to find any moment like that while bizarrely I've found an instance of Japanese OST being kept in the fighting foodons dub.4Kids actually kept more of the background music then TCPI ever has(at least in the show, strange how they don't replace the OST in the movies yet they do it with the show) which is weird to think of considering 4Kids totally replaced the soundtrack of every other show they dubbed. Guess they didn't have the budget to replace all of the music with Pokemon since it was their first time dubbing anime.