All 68 and 69 U.S. model Z/28s had smog pumps (A.I.R.).
In 67, smog pumps were only required on the California sold vehicles.
68 all the Z motors were MO coded. 69 all were DZ.
In 67, the engines without smog pumps were coded MO.
With smog pump it would be coded MP.
http://www.camaros.org/drivetrain.shtml#PadStamps