Cuda,
All Pontiacs start with 2 (PMD) then 2 more numbers indicating the body type (33) Tempest/T-37 then 2 more numbers indicating body style (37) 2 dr ht.. Then the pland code. Then the actual serial number of the vehicle. This was up thru '71. Try this site and see more.
http://www.wallaceracing.com GTO's were body type 42 from 66-71. They were options on the LeMans in '64-'65 & '72-'73 and of course an option on the Ventura for '74.
Is the WW code a code on the front of the block on the right side (passenger side) of the engine beside the water pump just under the head?