At least back when my bicycle was made in August 1981, the serial number made sense, assuming you know the syntax.

My bike’s serial number starts with H1???

H is the 8th letter of the alphabet, so that was made in the 8th month, August.

1 is the last digit of the year in the 1980s, so 1981.

Things were almost so much simpler once upon a time, but yeah the coding of model names and serial numbers has definitely gotten more complicated over the years decades…