Do "Civil Aviation Regulations" and "Aeronautics Bulletins" still have any legal authority today?
No, except for a type certification rule.


  Aug 23, 1958: 
  
  President Eisenhower signed the Federal Aviation Act of 1958 (P.L.
  85-726) into law. Treating comprehensively the Federal role in
  fostering and regulating civil aeronautics and air commerce, the new
  statute repealed the Air Commerce Act of 1926, the Civil Aeronautics
  Act of 1938, the Airways Modernization Act of 1957, and those portions
  of the various Presidential reorganization plans dealing with civil
  aviation.


The aviation law slate was wiped clean and started fresh with the FAA, although many of the principles in the aeronautical bulletins and the Civil Aviation Regulations were clearly incorporated into the FARs we know today.