Actually they mostly seem to be white armor with yellow marking over a black/dark grey jumpsuit. Nice nod to the original concept. Mama Wren appears to be the clan leader so she have much more prominent markings including a almost entirely yellow helmet. So yeah, it looks like the colours are a clan specific thing.
It seems somewhat flexible and at least partly dependent of allegiance given that all of the soldiers in Deathwatch were uniformly displaying a blue/grey/silver pallet under House Vizla and one assumes most of those were from various different clans. Indeed we know for a fact Bo-Katan was at least born into of Clan Kryze, yet she wore Vizla's colours. Also notable is that Vizla's soldiers that sided with Maul switched to Dathomiri inspired decoration.
But yeah, Boba's armor seemed to have mostly the same green colour scheme so there's probably a clan out there with those markings. Indeed, there's a good chance that the symbol of that clan is that is the one on the chestplate as IIRC TCW established that the right shoulder is the unit symbol while the left is a rank insignia (I may have that backwards.)
That the symbol is so prominent (I don't think any other Mandalorians had chest symbols except Vizla in later appearances) and the green colour is so dominant may indicate this was the armor of a clan leader. Which would make sense if Fett really took it as a trophy.
Sounds like an opportunity to reinterpret the Jaster Mereel and/or Jodo Kast stories to me.