Do I Spy a 50th???

[71swb4x4]

Now I understand what you are saying. You would like documentation that tells you that the 551 paint code is the indicator, along with what else the 50th anniversary entails. I can't help you there, but I certainly understand why you would want documentation.

I believe that the 551 paint code does specify a 50th anniversary truck. Here is what I can offer:
In 1955 Chevrolet produced it's 50 millionth auto. To celebrate they offered the Bel Aire in a gold color, which was specified by the 689 paint code. It is believed by some that 5,000 were produced. The special part on these was the paint and interior, but the cars could be ordered with any of the optional engines, and other options. It was not a full package of options, simply special colors and then normal options could be added.
In 1962 Chevrolet celebrated the 50th anniversary of Chevrolet by offering a gold paint (code 927) Impala. This could be ordered by anyone, there was not a minimum or maximum number of cars, and it could be ordered with any of the normal options.
In 1968 Chevrolet celebrated the 50th anniverary of their trucks by offering the 50th anniverary Chevrolet truck. This could be ordered as a pickup, van or elcamino. Again, it was a special paint/interior, but could be ordered with the normal options, just as it happened with the 50 millionth anniverary promotion and the 50th anniverary of Chevrolet promotion.

I am not trying to convince you of anything, just offering what I know. This information comes from what I have read. I do not have any documentation from Chevrolet supporting any of it. It may or may not be out there. I have never looked for it.