In the most recent installment of his very useful Legal Theory Lexicon, this one on functional explanations, Larry Solum (Georgetown) concludes by noting:

Let me conclude with a very short diatribe. Legal theorists need a basic understanding of positive legal theory. (I hope this is obvious to everyone!) That means that legal academics should, at a minimum, have a working familiarity with the general concepts of the methodology and theory of the social sciences, including basic ideas about the role of functionalist explanations. But almost no law schools (even the elite ones that train most academics) offer courses in the methodology of positive legal theory! That's bad. Real bad. 

Of course, as Larry knows, many legal philosophers do not think positive theories are particularly relevant to philosophical questions, though I am not one of them.  I do agree with his basic point that some grasp of foundational issues about the social sciences would be useful, including understanding methodological individualism vs. holism, the nature of functional explanations, and the relationship between functional and causal explanation.   I will note that Michael Forster and I do teach a lot of this material in connection with teaching Marx in various seminars, including, again, this Winter Quarter (while we do use Elster, and some G.A. Cohen, we actually use a 1986 paper by Peter Railton on "Explanatory  Asymmetry in Historical Materialism" (from Ethics) as the counterpoint to Elster, though Cohen ended up endorsing something like this view [I think]).  Whether all law teachers should be required to have had a course in the methodology of the social sciences is a harder question, but it surely couldn't hurt!