Blizzard has stated that the two popular guild perks from the original version of Cataclysm, Have Group Will Travel and Cash Flow, will not be present in Cataclysm Classic.
Both spells were part of the Guild Level system in the original version of Cataclysm, being earned at Level 15 (for rank 2 Cash Flow) and Level 20 (for Have Group, Will Travel).
However, Blizzard recently announced that several changes were being made to Cataclysm Classic, including the removal of the Guild Level system altogether.
While other Guild Perks seem to remain, either being given to players instantly upon joining a Guild or having been granted as a baseline to players regardless of Guild status, the loss of these two, in particular, will likely take some getting used to for players that leveled their way through Deathwing's initial assault on Azeroth.