Estate sale find - National Currency question
I bought the note pictured below at a local estate sale yesterday. I don't think I have ever bought a large size National Currency note before. The price was right and so I couldn't pass it up. I collect Colorado-related items, so this is a neat thing for me. I know that this issuing town has a premium value due to scarcity and mining history. I found a similar one that sold on Heritage in 2007:
From the somewhat limited familiarity that I have with these National Bank Notes, I understand that there are three different "Third Charter Period" issues:
1st: red seal & serial numbers, "1902 - 1908" date on back;
2nd: blue seal & serial numbers, "1902 - 1908" date on back;
3rd: blue seal & serial numbers, no date on back.
The Heritage note and my note appear to be the same 3rd issue, with the same signatures (Fr. 604).
My note has some differences:
two large blue "W" next to the charter numbers;
lower left serial number is different than the upper right serial number;
the upper right serial number has a letter prefix and a letter suffix.
The Heritage note:
does not have the large blue "W";
the lower left serial number is the same as the upper right serial number;
the serial numbers do not have any letter prefix or suffix.
This makes me think maybe there should be a classification for a "4th" issue, since the differences are significant ? Do collectors in general care about these particular differences and/or do they attempt to acquire both types for a "complete" collection ?