Is carob bean cooked when used as a thickener?
Carob bean gum is extracted through industrial processes, not generally reproducible at home.

Per CAROB BEAN GUM 
Chemical and Technical Assessment (CTA) 


  The seeds are  dehusked by treating the kernels with dilute sulfuric
  acid or with thermal mechanical treatment, elimination  of the germ
  followed by milling and screening of the endosperm (native carob bean
  gum). The gum may be  washed with ethanol or isopropanol to control
  the microbiological load (washed carob bean gum). It may  also be
  further clarified (purified, extracted) by dispersing in hot water,
  recovery with isopropanol or  ethanol, filtering, drying and milling,
  which is called as clarified (purified, extracted) carob bean gum. 
  Clarified carob bean gum in the market is normally standardized with
  sugars for viscosity and /or reactivity.