Dealers, when repainting earlier tractors, reputedly would use the flashy new Ford Blue to make the machines look newer. And owners would often do the same. So it is pretty common. Interestingly enough, the blue n's I see always seem to be in about the same state of decay, with the blue peeling off to reveal rust or red paint, so one suspects painting them blue enjoyed a brief vogue shortly after Ford came out with the new color.
Mine had big, stiff, 8x16 truck tires on my 8n when I got it. They were pretty necessary with the loader, but hard steering after I got rid of the loader. Now I'm running old Harley 16" tires which are in endless, free supply at your local Harley dealer, and work quite nicely, especially considering the price.