Unity USA still sells Spotlights that are very much like what they produced in the 40' and 50's. There is very minor changes in design that only the very knowledgeable person would notice.
Here is what you will need to buy for a 1947 to 1948 Kaiser or Frazer
Web address
http://unityusa.com1 each - Base Spotlight P/N 125A-4535-U-I 6V Spotlight $239.58
1 each – #11 Installation kit includes the mounting bracket, gasket (when needed), fasteners, trim pieces, and drill bushing. $42.59
1 each - 6295-KF Kaiser-Fraiser Raised Ornament for 50, 125, 225, and 250 series spotlights. $11.98
Total $294.15 (does not include shipping charges)
Note: I have a copy of the drill template for the 1947 - 50 Kaiser or Frazer