Every faction is recieving the battlemech units it historiclly had, or as close as I can get, and there is not alot of reliable information on them outside of the Historical: War of 3039, which focuses almost entirely on the DCMS, AFFS, and LCAF. However, since that would make certain factions essentially unplayable(CC, SIC, FRR), those factions are being bolstered in other ways to make them more attractive. In the case of the CC, considering their dependance on Mercs, I'm currently leaning at giving them some sort of bonus on the mercenary market, or perhaps, given their propensity for relying on mercs, I might allow them to choose from a handful of the units they historiclly had at the time, and giving them advanced access(essentially they'd have a 'right of first refusal' clause in their past contract, which the MRBC would be honoring).
I haven't decided exactly what, so don't get your hopes up on that just yet. I'm still scouring the books for information on the formations, and I'm also putting together aerospace units from scratch, so you atleast have a little MP to play with.
