Unfortunately, you stepped into what may easily be one of the most confusing naming issues in modern numismatics.
All 1988's have a gap between the A & M of America on the reverse, making them a
Wide AM, but a few 1988's have a different reverse design and for an unknown reason PCGS decided to label the variety with the different reverse design a "
WAM".
As Coop pointed out, the key pickup on the 1988 "
WAM" is actually the different design on the initial FG, not the gap between A & M.