When I bought my 1990 W250 new, I got a thank you letter from the salesman and the dealer owner within a week, along with a 1990-1991 calendar with me, my friends, and the salesman in front of the truck in the dealer lot. Then a followup letter about 2 months later.
When we bought the Jeep Liberty in 2002 we got a followup letter from the dealer (Carmax) that included a handwritten note from our saleslady.
My wife only remembers getting the boilerplate corporate followups from our purchase of her 2006 Mini Cooper S.