I've given this some serious thought. My Part & Body Ilustrations CD shows one washer. If you order the h/w, you get one washer. Hmm. I'll bet a mistake was made on the original drawings at FORD and it slipped by for some time. As many of us know, who have worked in an engineering environment, especially back in the pencil and T-square days, changing documentation, such as drawings, costs time and money. There probably should have been two washers and I plan on doing just that.
On edit: Just had a conversation with a good friend who is a Mechanical Engineer, who for years also did engineering drawings, and agreed with my analysis. Someone screwed up and later it was decided to ignore the problem because it wasn't a safety issue and would cost time, money and some adjustment on the assembly like. He added that the guys on the assembly like probably brought this up but were told to ignore it. It is a small problem but interesting.