I think i found the answer for the date codes on 1966 and 1967 (early?) smog pumps. as in the pictures of third post, they have 5 digit numbers, stamped into a pad on the side of the aluminum housing, which translate to:
DDDY# DDD= julian calander day, Y= year, # = shift code ?
I dug out a few smog pumps and found: 12471 which would be: May 4 1967
28461 which would be: Oct 11 1966
25061 which would be: Sept 7 1966
15771 which would be: June 6 1967
from third posting 02062 would be Jan 20 1966
what do you think?
found clue on camero site here:
http://www.camaros.org/emissions.shtml