while people are here I'm 99.9% sure I've cracked what the buttons on gerard's long live outfit are (photo below by joanna foster)
i picked up quickly that these were not your typical puffy crowns (think the British crown), but could not figure out for the life of me what it actually was....until yesterday when I got insanely lucky with google reverse image searching.
it's because it's a crown that doesn't actually exist, or didn't for very long because its model got stolen, but it was meant to be the german state crown (images from the Wikipedia article about it)
these buttons specifically, however, belong to the german/prussian pre-ww1 colonial army:
these are INCREDIBLY hard to find, by the way. i was looking at a sold listing earlier and it was like 30 bucks for literally 3 of these (non-reproduction), and the reproduction ones are made by literally one guy in the entire world. I am NOT exaggerating even a little bit when I say that, it is in fact just the one guy.
TL;DR: the crowns on gerard's lltbp outfit are almost definitely german kaiser crowns on a button design from pre-1900 and the costume designers either got insanely lucky in finding a full set of 16 of these or they paid a shitton of money to get reproduction buttons. THE END