Yup - I also recently saw Corey on Barney Miller as an Amish man.
He also did another Barney as an elderly ex-con who commits a crime because he can't cope with the outside world.
Outside of James Gregory, William Windom and Corey, I am hard pressed to remember another TOS actor who appeared on Barney. Barney Miller had its own little roster of bit players who they used about once or twice a year each as various perps/victims. People like Candy Azzara, Phil Leeds , and especially Ken Tigar, who played a nut who thought he was a werewolf - and then later was possessed, and another who thought he was Christ.