You bet that was worth pulling out! Serial Numbers on currency always open up unique collecting options that you don't have with coins. Low serial numbers are a big one. So are mismatched digits and RADAR notes. I personally know of a case of a dog earned $1 Silver Certificate (that was probably one of the common 1935 series) selling for $300 that had all sevens across in the serial number. This was at an auction in a small rural town in the 1980s. Imagine what that kind of note would bring today ---.