Reuní el siguiente Applescript que resolvió mi problema. Para obtener la función de titlecase, descargué e instalé "Satimage osax" de enlace .
tell application "Contacts"
set All_Contacts to every person whose name contains "test"
--set All_Contacts to every person
tell me to display dialog "Are you sure you want me to correct city of " & (count of All_Contacts) & " contacts?"
repeat with My_Contact in All_Contacts
set All_Addresses to (every address of My_Contact)
repeat with Current_Address in All_Addresses
set city of Current_Address to (titlecase (get city of Current_Address))
end repeat
end repeat
save
end tell