The hands on approach often works best.
They could have used someone to do that in Hong Kong and Taiwan. If the foreign releases of movies are anything to go on film makers in those markets lifted a lot of commercial music and music from foreign films without permission in the '70s and '80s. For example I've heard Riz Ortolani's theme to the film Day of Anger used as the theme to several '70s martial arts films, while the 1976 film Master of the Flying Guillotine used music from Tangerine Dream, Neu!, and Kraftwerk. So I'd be entirely unsurprised if library music was used without permission as well. Having said that Shaw Brothers, once the dominant movie studio in Hong Kong, seems to have had an agreement with De Wolfe Music in the '70s, and their tracks turned up in Shaw films.
(Shaw is an Anglicisation of Shao, the family name of the brothers who started the studio.)