1950's - 1960's Cadillac Buick Olds Chevy GM (?)

CASCO 12V Lighter

Casco 12V chrome knob dash lighter and socket, that I acquired with a grouping of early '50s Cadillac parts. The knob does not look early-'50s Cadillac to me, so I'm guessing it may be another GM brand (Chevrolet, Oldsmobile, Buick or Pontiac) - I am not sure.  Please identify it from the photos and tape measure in them. 

Knob is in good original condition with nice shine, but some minor pitting. 

Lighter and socket are both untested electrically, with some surface rust.

Please check my other auctions and eBay Store, as I'm in the process of liquidating a 1950's-1980's Cadillac parts dealer's inventory and have a lot more Cad parts to sell. Will be adding new items to the store every week.