Thanks stock49 for the pictures.
I did some color "matching" with my excel/powerpoint palette, here is what it likes to match them best.
Pure "Gray" has RGB with red=green=blue
eg 200red 200green 200blue etc.

1949 gray
RGB= 170red 190green 220blue
Nearly gray but a tiny hint of green and a bigger hint of blue
Try it!
Then just use one of the pure gray colors in excel/ppt - definitely too "gray".

1953 blue
RGB= 80red 130green 210blue
Much more green and blue so color looks clearly blue

So, I guess I can see why the early color (29-52) gets called gray-blue even tho it looks pretty much gray - there is a hint of blue. I don't have an older six but it sure looks like the exact right color is needed for a good match.

I actually grew up with the Model A Ford, and it always bugged me to see the "wrong green" on the A - so as these 30s-40s-50s cars get restored the proper shade matters.