I think the answers to your questions are here:

http://www.thesamba.com/vw/forum/viewtopic.php?t=599095

On Mar 30, 2015, at 6:13 PM, Jim Felder <jim.felder@gmail.com> wrote:

> Not sure about the exact name, but I would describe them as the small brass
> things shaped like the outline of the numeral one that fit to the key when
> it is put into a lock. The ones I have have a 1, 2, 3, or 4 stamped into
> them.
>
> When I shared a few with a list member he said "you sent me 1 through four.
> Do you have four through eight?" I checked with another list member who
> happens to be my brother and his only go through four. It could be a family
> curse.
>
> What's the story here? What comprises a complete set?
>
> Thanks,
>
> Jim