Kiernan Shipka, who played Sally Draper on Mad Men, has listed off her memories of the many actors who played her on-screen brother, Bobby, throughout the series.
Shipka was only 6 years old when she began working on the show, and while she made it all the way to the series finale, she notes that she wasn't in the pilot—"I have no memories of Pilot Bobby... The pilot was filmed in New York and Sally was played by the director's daughter." Both Bobby and Sally are only seen at the end of the pilot, when Don returns from Manhattan and looks in on them while they sleep.
Here's an excerpt from Shipka's list—you can read the full thing here.
MY MEMORIES OF THE BOBBY DRAPERS
Bucket Head Bobby A little known fact is that this Bobby was an entirely different Bobby. He was anointed "Bucket Head Bobby." We didn't really bond, because we only worked together for a few hours. He seemed chill.
Pillow Face Bobby Another Bobby many people don't know about is "Pillow Face Bobby," because he was directed to bury his face into the pillow and not turn towards camera. Like with the other Supplemental Bobby Drapers, we didn't chat too much, but he seemed very nice.
Bobby #3 Jared Gilmore ditched for Once Upon A Time, but he was great! He loved Sizzler and eating packets of straight sugar.
Bobby #4 Mason Vale Cotton stuck with us through the end. He's an awesome kid and had the longest run out of all the bros. He loves football and can rock a tux.
Now we need an entire oral history from the many Bobby Drapers—remember when Bobby #3, Jared Gilmore, very publicly insinuated January Jones was not a very nice person? "Be careful around January," he said in an interview, "She's not as approachable as the others. She's really serious about what she does. Everyone else is so nice."