Are carbon fiber/composite aircraft at greater risk from lightning?
From Boeing's AERO:


  Areas that have the greatest likelihood of a direct lightning attachment incorporate some type of lightning protection. Boeing performs testing that ensures the adequacy of lightning protection. Composite parts that are in lightning-strike prone areas must have appropriate lightning protection.
  
  Lightning protection on airplanes may include:
  
  
  Wire bundle shields.
  Ground straps.
  Composite structure expanded foils, wire mesh, aluminum flame spray coating, embedded metallic wire, metallic picture frames, diverter strips, metallic foil liners, coated glass fabric, and bonded aluminum foil.
  


That suggests for composite areas that are vulnerable to lightning strikes, extra measures are taken to enhance the conductivity.