The Serial Number on BMW VIN's are the last 7 digits. On newer models they are letters and numbers, but for older models such as the E12 and E28 they're usually just numbers.
M535i LHD, model code 4701 (some were DG01), model year 1980:E12 Serial Numbers
4 145 001 - 4 145 408
Model year 1981:
4 145 409 - 4 145 960
M535i RHD, model code 4702 (some were DG02), model year 1981:
4 148 001 - 4 148 450
DG01 and DG02 were more prevalent in later production dates than early. People usually say DG's were used in 1981 and 47's were used in 1980. BMW officially labels the VIN's 47xx.
Note that South African (RHD) 535i's were produced from Feb 1982 to Feb 1984 535i (e12). The model type was 4709. Production was 600 in 1982, 404 in 1983 and 4 units in 1984. The South African 535i had an overdrive gearbox and the front spoiler & bumper were not like the combination plastic unit common to the German built M535i. A unique thing to all South African e12 cars built from 1982 to 1984, regardless of engine & version, is that they had E28 interiors, carpet, door panels, dashboard and the check control system. Note, that these are NOT offically M535i's, but South African 535i's. That is the official designation.
These cars are more likely to have a 3.25 LSD rear end rather than
the 3.07 LSD in a normal production M535i. But they should still have all the rest of the
components of an M535i including the 3453cc engine, close-ratio transmission (usually), Recaro
seats (or even the Motorsport cloth ASS seats that Dave Spencer's car has), and the M535i airdam
and/or rear spoiler. They're a unique piece of history that should prove to be very nearly on
parr with the value of a standard production E12 M535i.