Whatever constitutes as punk seems debatable to some but I’d say it’s practically the marriage of various underground American rock acts like Death and to some extent Velvet Underground and glam rock like New York Dolls and David Bowie (some of his albums were cited as an influence on the emerging punk sound) with Blondie, Wayne County and the Electric Chairs/Backstreet Boys and The Ramones being early American punk prototypes (in fact, one of the Ramones started out in a glam band).
Considering that Bowie’s cited as an influence on subsequent punk bands, keep in mind The Clash’s Mick Jones and Sex Pistols’s Sid Vicious were both influenced by him and Mick’s colleague Paul Simonon doubled for Bowie proper. Not to mention Sex Pistols manager Malcolm McLaren also managed the New York Dolls so glam’s influence on punk rock’s going to be inevitably this close and strong.
So much so that 70s punk’s the natural evolution of glam rock and the profound glam influence on 70s punk should be enough to distinguish it from subsequent permutations like hardcore punk. If it sounds weird, what David Bowie, New York Dolls, Blondie and Jayne/Wayne County wore seemed tame in comparison were outrageous and trashy enough to inspire subsequent punkers.
Bowie certainly didn’t sport liberty spikes but the spiky hair’s there as with the overall purposely trashy fashion sense (same with Jayne County and New York Dolls). If they seem far-removed from contemporary expectations of punk keep in mind they’re the prototypes of it (hence proto-punk and glam punk).
If punk’s the direct development of glam, both of them are founded on the basis of being purposely trashy hence the over the top fashion going hand in hand with crude rock music. It seems lost in some hardcore bands but it’s much more evident in the early 70s.