These are interesting issues. I can understand why given the rhetoric associated with Friedman's methodology paper, economists think that Friedman is not a very subtle philosopher of science. Nevertheless, I have (partially) defended Friedman's insights and subtlety as a philosopher of science in E. Schliesser (2005) "Galilean Reflections on Milton Friedman?s "Methodology of Positive Economics," with Thoughts on Vernon Smith?s "Economics in the Laboratory," Philosophy of the Social Sciences, Vol. 35, No. 1, 50-74. (http://pos.sagepub.com/cgi/content/abstract/35/1/50). Importantly, my defense does not rest on any of the usual issues pertaining to the F-Twist and false assumptions. Rather, Friedman anticipates much discussion that comes out of post-Kuhnian and Post-Quinean philosophy of science that focuses on evidential practices, heuristics in science, and the way in which theory frames research. (Sadly, the ways in which Friedman is insightful on
 methodological issues did not get reflected in the rhetoric of "Chicago''s official philosophy of science," although it may well have been very important to the practice of Chicago economics. In a further twist, I think I have showed that Vernon's Smith's defense of the methodology of experimental economics is surprisingly indebted to some of the unappreciated insights in Friedman. ) Unfortunately, here Galison's concept of a 'trading zone's' is irrelevant because there is no evidence that Friedman's work influenced the development of philosophical theory on such matters. (I would love to claim him as one of my intellectual 'ancestors'!) Of course, I should be more tentative about this--we don't know to what degree there was interaction between the philosophers, including Carnap (the teacher of my teacher), and the economists at Chicago in the late 40s and early 1950s. I have wondered, for example about a connection between Savage and Carnap. Also,
 there is evidence of a correspondence between Stigler and Tom Kuhn, and this has some neat twists to it some of which I will write up in near future. 

Eric Schliesser