Gloria Gibson

I don’t think this was filmed as early as you think. The original opening sequence for Season 4 had a different ending clip in the Tiffany credits at first. Later in the season, the one from Angels On Campus where Shelley is in red and has her hair straight - the clip that is shown on the dvd now - was inserted as a second version or second edition of the opening sequence replacing the original clip that was used. Someone has actually posted the rare original opening credits to Season 4 on YouTube. I remember the change as well. So for those reasons, I believe the Angels on Campus episode was indeed filmed later and they chose a clip to replace Shelley’s opening sequence with. But to your point, I think this episode would have for sure made a better introduction to the Tiffany character had they aired it earlier in the season. However, I don’t think the regular stable of writers on staff thought highly of Shelley Hack’s acting ability and thus didn’t want to write for her so it took new outside writers to finally create and produce a decent Tiffany-centric character-establishing episode and get it in the can.