A or B (shift or plant, I've never seen it confirmed)
Then Julian date, then year (single digit).
'A 032 9' is Feb 1, 69.
Steering gear housing cast date: 363 (Friday 12-29-67)
Steering gear assemble date: B 036 8 (Shift or plant B on Monday 2-5-68)
Van Nuys build date: 02C
I just wanted to be sure we were deciphering the code correctly because firez's '68 Van Nuys built Z/28 was built after mine (02E), yet his steering gear was cast and assembled months before mine.