I'm not quite up to date with the timeline, but has it been established yet when the Diamond Sharks reverted to Sea Foxes? So far there was only something along the lines of "prior to 3100".
The Black Hawk writeup makes it clear that they were still the Diamond Sharks at the formation of the RotS but were already Sea Foxes by 3096 when the Dragoons first deployed the Black Hawk 2 variant that had been devised by Clan Sea Fox.
In the Koshi writeup the Clan is referred to as the (Diamond) Sharks after 3091 and (arguably) into 3093 (ambigous wording).
Funny tidbit on the sidelines: The Black Hawk is built with a Spar 3c Tight Band targeting/tracking system which appears to be quite an illustrious piece of hardware. According to TRO3025, the Stalker had "the best fire control system available" but as of 3025, few Stalkers still had the original system. The (apocryphal) optional rules for individual fire control systems from BattleTechnology: The Lost Issues assign the original Spar 3c Tight Band a flat out -2 targeting modifier, making it one of the best systems available. In the fluff text, the academy instructor says that if anyone happens to obtain a functional Spar 3c Tight Band, he knows that a Barony was offered in exchange for one.
It is weird to see a system developed specifically for the Stalker's weapon loadout being mounted on a 50-ton 'Mech with four SSRM4 and 2 ERLLs. Well, at least a vaguely similar armament...