This is the most obvious. Niekro was traded to the Padres early in the 1969 season. He was moved to the Tigers over the winter. He's pictured from 1967 or 1968, wearing a Cubs road uniform.
You'll have to take my word for it with these three, since the 1969 Cubs road uniform was a more plain gray with no piping around the neck. All three of these players were with the '69 Cubs. Selma and Phillips are older looking than past cards, so I'm saying these were taken in 1969. Nye has to be in a Cubs uniform since that is the only MLB team he played with prior to his trade to the Cardinals.