1. did WP HAVE a mars light on their F3/F7's? 2. if they did, was it the upper light or the lower light on the nose of the A unit?
Do you know about the Western Pacific Railroad Museum? They have pages about different F-units. This one shows #805-A: https://www.wplives.org/locomotivepages/d_wp805a.html If I'm seeing it correctly, it has a gyrating light in the upper position. Most of the other units pictured have only a single headlight (dual sealed-beam I think).