New $100 Bill Question?

Off the top of my head I seem to recall the first letter of the serial number is the reserve district.

which also is apparently represented by the letter and number below the left serial number
http://www.uspapermoney.info/general/note.html

I encountered this issue the other day when I went to catalogue all my notes.

The more recent notes dont have the issuing banks name in the black seal like they had in the past. The way I figured it you have the serial number and just below another letter printed in the same typeface. That letter seemed to be the code for the issuing bank.

The Red Book also lists some of the issuing banks city rather than states (so for instance the note says Georgia and the book says Atlanta...not a problem if you are aware of American geography but a potential headscratcher if you haven't traveled the states)

The Red Book of American currency seems to be quite a good book, but I thought that it should have mentioned these couple of things.

Here are maps about the different federal districts:
http://www.federalreserve.gov/otherfrb.htm
http://www.glotter.com/entry-1844

And for quite a few years now (maybe over 10 years), only the one and two dollar notes list the federal district stamp on it. The rest have the second letter of the serial # as the district letter.

The BEP lists some info on the notes:
http://www.moneyfactory.gov/small1denom.html