[Mr70]

I've found Power Steering Pumps that were dated.
Stamped about half way up the side of the reservoir,facing the waterpump near the neck.
Example:
Assembled on:123 4 5 0
123=Day of year
4=Shift
5=Line
0=Last digit of year

I've found Power Steering Hoses,Hi-Psi & return were also dated,I believe by two possible plants,printed on side of hose.
Manufactured on:123 0 1
123=Day of year
0=Last digit of year
1=Shift