Kelley lists two $10s and three $20s as far as type 2's for Ch. 3906 (not including your SN A001908).  Best Ty. 2 $10 was VF-XF and Ty. 1's out number 2's by about 3:1.   Not sure if T&P has more listed but certainly a great find (assuming she doesn't have SN 1909-2009 stashed away in the back) !  Appears to be a single bank town and a County (Fayette) with only 4 National Banks (good luck finding the FNB of Flatonia $50 Brown Back)!

On the FRB of Dallas, any idea why the black bar to the right of Governor?  Maybe that's common as I don't look at the FRBs much. [yes, appears to be part of the Fed Reserve letter printing, but why?]

Once again, my compliments to your keen eye. The strip appears on all small FRBNs. As you can see, it is designed to block out the word "President." Whether that was a mistake in the plates, I don't know but it is certainly interesting. Perhaps the engraver mistakenly put "President" instead of "Governor" ?? I don't know but it is certainly interesting. It remind me of the black strip seen on Fr-1225's. Let us know if you find out why!

Actually, if you see the left side of the note, the black strip is intended to cover the word "Cashier"." Perhas the plates were originally intended for NBN's and then were adapted for FRBN's? This must be known within the hobby. Great mystery!!

The New York FRBN's shown above have "Deputy Governor" on the left of the note but observe the Dallas FRBN I posted. It still says "Cashier" Was Harris the Deputy Governor of the Dallas Fed or a cashier!!!!!???? You have opened a Pandora's Box!!

The 100 consecutive Fr-1620*'s....

Wow, a hundred consecutive stars!

There are some nice Dallas Fed Reserve Bank Notes collections competing and all denoms have Cashier (not blacked out) and Governor (with President blacked out).  I guess Dallas ran their operation differently.  By the way, I like the collage of different shifts of the overprinted bar showing the underlying engraving (of Cashier and President).  I'm sure you're right about one generic front for both small size nationals and Fed Reserve Bank Notes--just needed to overprint correct titles of the signatories (and black out the extraneous titles found on small size nationals.

So, now I have to change subject to nationals of course... Here's a Large size 1902 PB from the First NB of Fostoria, OH, Ch. #2831.  It's rather scarce.  Kelley's census includes bank officers for some banks with Ohio covered fairly well.  Fostoria long time President (1883-1935) would have been Andrew Emerine except the VP signed.  Cashier is R.S. Powley.  The VP signing was common enough that the FNB stamped Vice Prest. above the blacked out Prest.  Unfortunately, I can't make out the signature on my well used example.  Two better examples of 1902 PBs are in Heritage's archives, but are signed by Prest. Emerine.  Other notes I've seen will have a v or vice penned in front of Prest.  This is the first instance I've found of a stamp applied locally by the bank similar to what was done on Fed Reserve Bank notes blotting out the incorrect title.  This note (SN 11217 pp G) is in Kelley's census, so I guess I'm not the only one unable to decipher that signature.