Here's a charming letter from Irv. Sr to the Buick Zone Manager requesting that paperwork be initiated that will designate his son, Irv. Jr, as his successor on the dealer agreement. Of course, Irv Jr. is better known as our own Pete Reynolds.
It's also interesting to note that the letter was addressed to the Buick Zone office on Wilshire. After many years on Figueroa St, Buick moved into a mid-century modern high rise in 1953, in an area known as Wilshire Center, where many high rises sprouted in the early 1950's. The Ambassador Hotel and the Brown Derby were nearby.
Note also the graphic design of the letterhead, featuring the postwar Buick and GMC logos, a V8 logo in the lower corner, and Buick's famous tagline, "When better automobiles are built, Buick will build them" in a very period typefont.