I'd wager that the SEC didn't put out an offer they may have hinted that if MU were to apply they would likely receive a favorable response. The Baylor lawsuit is threatening the SEC for supposedly approaching A&M thus leading to the breakup of the Big XII-II-I. These conferences have to be careful that they don't open themselves up to more lawsuits.
As a resident of Missouri having to endure all the abuse for the Huskers leaving and stealing "Missouri's invite to the B1G" I will LMAO if this "source" blows another chance of getting into a better conference situation!!! When will they learn their lesson. Loose lips sinks ships.
If we pay attention to how this has worked with NU, CU, Pitt, Syracuse, the schools apply for membership and then and only then do the conferences vote to accept or deny new membership. I'm not sure A&M did it this way, they were a little too public with all the goings on and it has already ended up at least nipping them in the behind by delaying their full acceptance into the SEC.
It will be interesting to see if Bevo actually gives in to OU's demands, I'd be shocked if they do. If the expected implosion doesn't happen I can't imagine the new Big XII would be very attractive to new schools that would be quality additions to the conference.