Is there a standard format for pre-departure clearances?
I know nothing about PDCs, but it does seem that they are now standardized. One aircrew training site said in April 2014:


  For those of you capable of receiving a Predeparture Clearance (PDC),
  have you noticed a change since the first week of April? The FAA
  changed the way it issues PDCs. Gone are the days of trying to decide
  if you got a reroute in the PDC. The FAA recognized there was a
  problem with standardization with regards to reroutes


The article points to JO 7110.113, Procedures for Issuing Automated Clearances, which says:


  5. Explanation of Policy Changes. This order is revised to provide standardization of PDC clearances across the FAA.


I guess you can read the rest of the JO for more information, it means nothing to me :-)