BWC age determination according to chronograph models

Here are the dates of the market launch of various BWC chronographs:

1954 BWC Chronograph Landeron Cal 52 full calendar, moon display

1958 Chronograph Landeron Kal 51, hand-wound

1962 Chronograph Landeron Cal 24817 jewels, hand-wound

1968 Chronograph Valjoux Caliber 7711, hand-wound

1969 Chronograph Landeron Cal. 248, hard gold-plated

1972 BWC Chronograph Doublé Case

1972 Sailer Watch, stainless steel, hand-wound

1972 Chronograph stainless steel case, 17 jewels, hand-wound

1973 Chronograph Cal. 7733, 17 jewels, hand-wound

1977 Chronograph Cal Valjoux 7750, Date, Automatic

1990 Chronograph Cal. 7750, Day/Date, Automatic

1991 Chronograph Cal. 7760 Day/Date, hand-wound

1992 Chronograph Valjoux Cal. 7750, day/date, automatic

Source: Wolfgang Salm "Wristwatches"