I doubt they write a song specifically for it. They're in the late stages of recording their album, they won't put that on hold again to to write another song/score again (at least I hope they won't). Then when the album comes out they be too busy touring.
If they're on the soundtrack it'll probably be a song from the upcomming album.
I believe it could be Blackbirds, since there will be Aerialbots and Decepticon seekers also there will be a major battle between the Combaticons Bruticus Maximus against Superion.
I believe its Blackbirds mainly cos its the first single out frm thier album and I visualized the trailer with the song. It kinda clicques. SO LP make it Blackbirds. In fact, Blackbirds is a smashing title.