It could be the difference in my monitor, but the supposed 137 is a lighter shade of carmine than any of my 6 cent National Bank notes
The "139" is the opposite, it is darker than any 10 cent National bank note I have.
Here's a couple of pics of the stock book, all non grilled National Bank notes.
3¢, 6¢, & 10¢ National bank notes

10¢ Nationals
