Here's info on what year your Sachs Torpedo hub was made:
"On hubs made from 1958 to 1974, you will find a letter for the year on the hub-shell.
A = 1958, B = 1959, ( "J" and "Q" are not used )
In 1982, they went back to 'A' again.
On hubs made from 1975 to 1989, you will find 2 letters on the brake lever.
The one above is for the month.
The one below (important) is for the year. "