Yes and no.
The GMC updates the rules as given in the new world of darkness corebook, though it seems that the devs at Onyx Path want one central book and it doesn't look like nwod 2nd edition is going to be a reskin of the God-Machine Chronicle but something completely new. For example, reading the GMC infront of me now, it shows off the new Aspirations, Virtues and Vices and has a list of updated Merits, though it doesn't actually detail fully how to create a character, Attribute and skill distribution along with what the skills do (or how many Merit points your character gets), you still need the corebook for that. Demon, 2nd edition Vampire and 2nd edition Werewolf do tell you how to generate full characters though, same as Beast does, as will all the 2nd edition books. GMC does not though.
So the 2nd edition corebook is basically placing the old corebook and GMC rules update together, along with errata that's been picked up in the meantime and I'm sure there'll be some nice new art and fluff written pieces in there too.
Btw, flicked through Beast and it's pretty damn cool... Its a bit early days for me to comment just yet, but I totally plan to try and put a Beast character together and add them in my request thread, to learn more of the system and maybe write as one too.
Five main groups, which are basically Strength giants (Anakim), Darkness predators (Eshmaki), smothering Sea-Monsters (Makara), the Repulsive (Namtaru) and Watchful flyers (Ugallu).
Then they have a Hunger. These come under Power (getting one over others mostly), a Hoard (loads of stuff!), Prey (hunting/chasing/scaring people for the lulz), Punishment (pretty self-explanatory, punishing wrong-doers) and Ruin (smashing stuff up).
Lair is the power stat... Doesn't seem to have much in the way of a con for raising it too high aside from if the Lair is too big, privacy there becomes an issue and from a quick glance, looks like enemies may find it easier to catch you there, not sure about that though.
Legend and Life are the Virtue/Vice mechanic.
Legend is the way your Beast hunts and how their myth/legend will refer to them and the most terrifying aspect of them in one word. Acting in accordance with Legend gives back 1 willpower, acting as it to the Beast's detriment fully refills it.
Life is the little bit of humanity your Beast has behind closed doors, the last bit of humanity left if they fully fell to their Hunger. Though one the Beast's Soul (what seems to be a purely narrative description of what your Beast is under their human surface) can tear away if their Hunger is not being satisfied. Its the sympathetic trait of the Beast you make up. When acting in accordance to Life over Legend, you regain all Willpower.
Kinship needs a bit of clarification on first look (it is very cool as a concept, the Beast can form a familial bond with another nwod supernatural, outside of Demons), though it does link to Nightmares, one of two abilities the Beast gets, along with Atavisms. You get two of each and one Atavism must be one linked with your character's chosen Family. So that's the Disciplines/Gifts/Rites there.
Satiety is the morality score for a Beast. I like how it works a lot. I also like in chargen you can decide how easily your character is full or gets hungry, which affects it. Depending on what kind of character you build, one may come off from chargen higher in the score than another. :)
And that's your lot for now. :)