Hayek and Rawls about social justice: are the differences "more verbal than substantial"?

Hayek (theoretician of "the mirage of social justice") seems to be completely opposed to Rawls (author of "Theory of justice"), but the economist can have written that the differences between himself and the philosopher are "more verbal than substantial". In spite of opposed paradigms (evolutionism versus contractualism), the stages are quite comparable in the setting of norms (anti-utilitarianism, impartiality, experimentation) and induce two versions of the same conception of justice in society, through the content and the hierarchy of norms the two authors put forward (priority of liberty, fair increase of opportunity for everyone, better condition for the poorest people).