I agree with FJ5, I'd consider either correct but the silver with a "gold wash" is more predominant and was likely what they all had or were supposed to have as an anti corrosion metal finish, just some had less gold initially or it wore off quickly. I've noticed the same variables in many plated parts on most years, a high degree of variability, likely due to various parts suppliers, etc. having different plating processes, thier blue prints likely called out a corrosion resistance spec that was to be met regardless of the shade or tint of the actual color.

The trouble is that todays plating processes vary just as much, trying to duplicate older plating finishes can be an artistic challenge, I go through it all the time with carburetor parts.