Chris S
On the type plate in the engine compartment there is a seven figure number, this number shows the exact production date your syncro.
There was also a yellow label behind the right headlight, but which is probably missing by now.
The format for both is xx-x-xxxx
where the first 2x are the week of the year from 01 to 53
single x is the day of the week from 1 to 7 or more normally 1 to 5
and the last 4x is the year of manufacture
so 01-05-1989 is the first friday in jan 89.
This is also true with gearboxes and rear differentials as after the code sequence I.E. 4Z, AOK, etc there is a 5 figure nr, as in 4Zxxxxx this can be broken down to read first two = date, second two = month, fifth = year so 4Z25117 is a 4Z gearbox made on the 25-november-1987