Hey Kevin and Bill,
The Black arms are correct for a 74-75 , but some early 74's had bright ones, but we never see to many 1974's do we?
The black is to reduce glare from the sun.
I saw a 74 in Seattle once, it had bright ones and it was unrestored.
I would only make a comment on the judging sheet , no points deducted, if they were not black.
I will look into this more.
See you on the show field.
Jake