Havens may be the company that made the key blank or the locksmith who made the key. We had a Havens and a Youngs in the Milwaukee area during the 1970's-80's that had blanks with the store names on them.
There is no current reference to a "Havens" relative to a K-F dealership, but my list of almost 6,800 entries is not represented as complete.
To answer the question before it's asked, Each entry reflects a different franchise. New franchises were issued when a dealership's name changed so it was in the factory records, as well as address changes for the same reason. Also, remember that over the years, many cities had different K-F dealers in town (one closed a totally different one under different owner ship opened up.). It's estimated that somewhere between 10,000 and 13,500 franchises were issued over the years, and at least 4,000 Willys franchises were issued between 1945 and 1957; typically 600 or so Willys dealers were also K-F stores at any given time.