Unfortunately the reality of the data is that there is one linear quantity (time) and another quantity that has multiple correct answers at certain points of time (serial number). And then, at this period in time (1978 -> 1980) the serial numbers also made a jump from 39million to 44million...So, it is not an easy thing to do in the reverse direction, especially seeing as there is quite a hole in the data (very low density of extracts over this period, unlike the 60s). To give you an example, the extracts that are used on the website for this period are :
1980 : 2
1981 : 5
1982 : 4
1983 : 1
1984 : 1
1985 : 1
1986 : 3
but...
1966 : 25
1967 : 47
1968 : 40
1969 : 17
1970 : 40
And here one can see the fun in sequential order of serial number (see how it jump wildly around?)...
39926XXX 1978/9
44123XXX 1983/06
44819XXX 1980/4 ***
44819XXX 1979/2 ***
44821XXX 1980/12
45249XXX 1982/3
45250XXX 1982/04
45581XXX 1981/03 ***
45582XXX 1981/7
45582XXX 1981/7
45582XXX 1981/9
45583XXX 1981/11
45585XXX 1982/1
45585XXX 1982/1
47132XXX 1986/4
47132XXX 1984/3 ***
47133XXX 1986/6
47133XXX 1985/4 ***
Why? I really don't know, only thing which makes sense to me is a combination of the random-bin-theory amplified by the
quartz-crisis. The most common speedmaster that one sees for sale are 145.022-69's...and I guess at the time after the moon landing, these sold like hot-cakes, and production ramped up at the point where the quartz crisis kicked in, thus leaving a lot of movements on the shelf to be sold over the next decade...or something to that effect.
I hope that helps you on your hunt, however, truth be told, I can't say it helps me...I can't tell you what would be a good SN to look at based on 1 extract. I would guess you should look for a late 45.5 mil (even though the only extract from 1983 is a 44.1mil)...and try and get an extract of any watch that tickles your fancy (and please send it along!) although that will become costly at $125 a pop.
Click to expand...