You can see part of the string underwear French Stewart is wearing during the chip scene between Don and Dick.
After Sally runs into Mary's office toward the end of the episode, Mary goes from wearing her glasses to not wearing them between shots.
Dick: But she's nakeder than they are.
Mrs. Dubcek: But you see this is Michelangelo and this is... Well, this is Michael and Angelo.
Dick: I just don't see the difference. I mean you tell me this is meant for arousal and this is meant for ascetic appreciation. But when I look at them... Well this woman washing her sports car does nothing for me, but this woman with the apple and the snake... Well that's just hot.
Pitman: We all came into this world naked.
Dick: Well, I didn't.
Dick: Harry, are you naked or am I seeing things?
Harry: Actually it's a little of both.
When Sally speaks to Don about appearing in the magazine, her hair changes between shots (look at her bangs).