From my understanding of Classical pronunciation, the audio seems a little off.
I have always be taught that gn is pronounced like the 'ngn' in 'hangnail' ([ŋn] if you know IPA). So, I think it should sound closer to 'pung-namus' rather than 'pung-gamus' (I seem to hear [ŋg] where the 'gn' is).
That doesn't reflect most of the literature I have seen on the matter. They say /gn/ is realized as [ŋn] (Wheelock's and the Pocket OLD, which I had on hand, both list this as the pronunciation).
Where did you get your information? Genuinely curious what other sources say on the matter.
/ˈpuɡ.noː/ might be appropriate for pugnō in phonemic representation, but it is said to be realized phonetically as [ˈpʊŋnoː] in Classical Latin, which DL professes to teach. I would like to know if more recent studies have found otherwise.