The nail is OK but tacky.
If you want a nice, dark black pin, with sharp edges, which looks like it should be there, take the pin to wherever you purchase drill bits from and buy the appropriate size "LETTER DRILL"
From talking to old REMEs, they told me they always replaced the pins with new ones if they had them on hand.
We don't have that luxury, for the most part, so we have to make do with what we have.
The nail will do the job and it can be blued to color match, just doesn't seem to finish as nicely as the harder drill stem.
Check the stems until you find one that fits snugly, otherwise, it can and will fall out when least needed.
You can cold blue the shiny ends where you cut it off, or use a felt marker to cover the metal.
Each drill stem will provide at least three retaining pins.