Yes, if the discussion is about some specific videogame related things and not about the franchise.
"SLDF-era" is hardly specific to HB BT. Now, there is nothing wrong with starting your journey based in HB BT, but you will run into questions along the way. Some may be answered by carefull scrutiny of this particular game, others not. If one wishes full knowledge, it makes sense to branch out and seek other sources.
Many people who played WoW didn't play WC1-3, should they require to do so before playing to be on the loop, to have the right of an opinion?
If they wish to discuss, say, whether Tauren being Horde rather than Alliance makes sense or not, then yes, they should read up on the lore. In the case of Warcraft I-III, that is extremely fast. In the case of Battletech ... not so much.
There is not a disclaimer on Steam or Paradox telling you better read some novels or play some older games before playing this one.
No, because that knowledge is not required to play the game. If, however, you want to get into discussion of lore and canon, then that would very much be assumed.
The devs may have changed things about the lore or give a different direction, because it is a different game.
Unless otherwise noted, all canon from the original work is inherited by spin-offs. There is nothing in HB BT saying that what constitues SLDF-era 'Mechs has changed, so we should default to keeping the same set as always.
In addition to the above: If a game wishes to introduce something new and shiny, it will usually label it as a rare SLDF prototype or some such. This is not done to the Bull Shark. If the devs wanted the Bull Shark to be considered an HB-only SL 'Mech, why have they not hinted at it being so? Because in their minds, it is not SLDF, but clan, d'uh.