The study of word origins is known as etymology. Knowing this is useful if you want to do a data search, you type in "etymology of gow job" for instance.

Here's one quote from one source;
gow Look up gow at Dictionary.com
1915, "opium," from Cantonese yao-kao "opium," lit. "sap;" used as such by Raymond Chandler, etc.; by 1950s meaning had expanded to "pictures of nude or scantily clad women," hence gow job "flashy girl," which in teenager slang came to also mean "hot rod."

Nude women, hot cars.....................hmmmmm, sounds reasonable to me.

Here's another source from the late forties where gow job was noted as new terminology. So yes, it's an "invented" term, but appropriate to immediate post war world, perhaps somewhat earlier;
http://books.google.com/books?id=egx...DhzdYQU_iOWTa4