I can't hold onto a $20 long enough to look at the serial number, lol. Actually, I did find a star note $20 one time. I did not know anything about it other than seeing the star on it so I asked the local coin dealer and he told me more about them. I think I sold it for $21 plus shipping or something like that on
ebay.
It looks like your super low serial # was printed correctly, as it has the A1 designation for the first plate. Some of these low serials in high grades can bring some really good money. Could you imagine working at a bank and being able to buy up entire stacks with low digits or star notes, etc...