HeinOnline's American Law Institute Library has the most comprehensive collection of drafts for the Restatements of the Law.
Restatement, Third, The Law Governing Lawyers (1986-present)
Westlaw, available on the library's Westlaw computers, also includes select drafts for the Restatements of the Law.
Jenkins has select drafts in print and on micro in the library. Search the Jenkins' catalog for Restatement* Draft* "Law Governing Lawyers" for a full list of available drafts.