There’s usually a sync fee for TV spots, even for HBO. If not, the library involved is really low balling and hurting the business at large.
Royalties are a bit tricky with trailers / TV spots. They have to be treated the same as advertising, which involves submitting paperwork to the PROs.
If it’s on HBO on any other premium cable channel, the royalties probably won’t be worth the effort – the rates there are ridiculously low.
On the other hand, promos on network TV (like music behind “coming up tonight on Jimmy Kimmel”) pay out great royalties. Those are definitely worth chasing up on.