Kate, who in real life is not known for glamour, thought that would be a departure for her, so at the last minute she decided she wanted to be Sabrina Dunkin, the character that wore the furs and the beautiful outfits in the pilot.
After a contract dispute, Fawcett appeared on the show as a recurring guest, rather than a main cast member.
I think Shelley maybe took it too seriously.
After my first comment I did more research into the Pinto Jackson drove and found it indeed was a '77.