I am a novice here. The pic was too large for the forum limits. Could someone please tell me what the numbers below mean? This 50 pesos came with the following notations on the outside cover, this is not on the bill itself: S268b XF DF-41 11-89 I am guessing that 11-89 stands for November, 1989. Perhaps the S268b and DF-41 is some catalog# or something of that sort? Any help is appreciated. Thanks!