How would you find this currency classification system one of the clubs I belong to use?
1899 Silver certificate P338
1917 $2 US note P188
1934 $5 Silver note P414a
Check this link out, might give some direction.
The Pick catalog numbers are certainly plenty common for non-US notes. If your club is not US-only, then it makes sense to me.
Yes, these numbers are from the World Paper Money catalog by Albert Pick, United States section.
Thanks for the information. I'm not sure why the auction guy uses that catalog when Friedberg is almost universally the choice these days.