Noisebeam, your Lemans 12 is circa 1981-1983, probably closer to latter. At the time, it was an entry level model, about 2nd or 3rd from the bottom of the line. In the late 1970s it was constructed of hi-tensile steel but was gradually updated until, by the mid 1980s, it was a mid-range model with a Tange #2, butted, CrMo tubeset. Your sample is from the transitionary period when it used a Tange #5, plain gauge, CrMo, main triangle in conjunction with hi-tensile stays and forks.