In addition to the serial number, the BB on my 1979 Team Champion has the following glyphs:
- the numbers 050 (last digit looks sort of like a 6 in the photo, but it's a 0, though smaller than the one that precedes the 5.)
- the initials KAC (above the serial #)
- the letter P (or is it a d?) on the downtube portion
I've always called this a 52 cm bike, but if I measure from the BB center to bottom of the top tube it comes out to 50, so maybe the first item is the size?
Not sure what to make of the second item - maybe the initials of the maker?
No clue about the last item.
Extra points if you can explain the serial number.