Yes, it's hard to tell from the photos whether that's the actual color or it's discolored from age and exposure to light. If one were in front of the actual object, it would be immediately apparent because the discoloration would likely be uneven and would be nonexistent on areas not regularly exposed to light. There was a recent thread on the discoloration of plastics from that era. I believe the originating post stated it was due to the presence of the chemical bromine. The member who originated the thread also shared a recipe for a (very caustic) solution that would reverse the discoloration. The active ingredients were hydrogen peroxide and OxyClean, plus some thickening agents (I don't remember exactly what) to create a gel-like consistency. You just spread the stuff on the affected parts, set them out in the sunlight all day (Ironic since sunlight was the catalyst for the discoloration in the first place) and the rinse it off. I would include a link to that thread but I'm too lazy to look for it right now.