Though Barbara Anderson and Elizabeth Baur both worked on the series Ironside (1967), they never appeared together since Elizabeth Baur replaced Barbara Anderson. This situation is unique in TV reunion movies since the original series cast is usually used in lieu of replacement actors who join later in the series.
Even though Raymond Burr's characters Perry Mason and Robert Ironside are in different series and have no relation to each other, both had moved to Denver, Colorado at the time of their reunion movies which was the location that Raymond Burr preferred to work in.