Hi Rupert,
Did that steering knuckle repair kit # A 111 586 00 33 include a new kingpin for that price? If so, that's an excellent price!
Seems strange that a kingpin would wear in only 68,000mi......
When I did my LH kingpin, I also replaced the other 2 part numbers you mentioned. It was a terrible job (lots of rusted/frozen parts!), so while it was apart anyways, I wanted to replace as much as possible. As well, it sometimes is hard to tell exactly where the "play" is, unless you had your nose right in there when it was checked.
Will W14
1965 230SL 4spd
Victoria,BC