Crimson Fists are dark blue with red accents (notably the fist). The Rynns world stuff is a lovely throwback to some of the earliest fluff, and indeed the single battle mission included in Rogue Trader the battle at the farm.
https://wh40k.lexicanum.com/wiki/Crimson_Fists
I do sometimes feel like the Crimson Fists got the short end of the stick, after being the cover art for the seminal version of the game, they have been unfairly relegated into a lowly subordinate chapter, with Ultramarines taking their place on the colour wheel