In Mad Men Episode 3.08: Souvenir, Pete encounters Joan working at Bonwit Teller. He leaves with a replacement dress, but sharp-eyed fans noted that Pete’s bag was not Bonwit’s signature violet-covered package.
In Severance, Joan visits Bonwit Teller on a shopping spree. This time, Mad Men got the packaging right.
As the shot pans, you can see that Joan’s shopping spree didn’t start at Bonwit’s. The distinctive brown and white striped Henri Bendel packaging is also visible; this is at least the second store she’s visited.