You're right that IF they offered him $300 mill, that would not be a lowball offer.
Mookie has really thrown a twist into things by insisting that the offer was not that high. I don't understand why he would lie about it. Nor do I understand why, if he was lying, no one has refuted him. It's become one of those conspiracy-ish things.
As I say, I find it credible that Henry would make an offer below $300 mill, based on his offers to Lester and Bogey.