Dennis, there are bits and pieces of info available online. Until some old salt (or other better informed party) offers aid, here are some suggestions gleaned from that online info:
NRS -- Navy Recruiting Station NCTC -- Naval Construction Training Center USNTC -- United States Navy Training Center CB Det -- Construction Battalion Detachment CB ABCD -- Construction Battalion, Advanced Base Construction Depot
I couldn't find anything specifically apropos to WC RS USAI. Possibilities would be WC - West Coast; RS - Receiving (or Recruit) Station; USAI - ???