No , she acted in only 4 episodes as Mrs. Kravitz’s sister after the original Mrs. K actress passed away .
After Alice Pearce, the original "Gladys Kravitz" passed away, they needed someone to temporarily fill in until they could find a new actress for the role (which went to Sandra Gould.) Mary Grace Canfield played Abner Kravitz' sister, Harriet Kravitz, who was staying with him while Gladys was "out of town." (Back then, very few sitcom characters died - they always went "out of town.")