John Deere company hired a Designer to improve the looks of there tractors. Henry Dreyfuss was his name, anyway he designed a hood and grill for the tractor(styled). Unstyled has no hood or grill. Here's a pics of a styled JD H and a unstyled JD A.
I'm a blue guy but have always heard the term and was reading the latest issue of Antique Power yesterday when it was brought up in an article and was puzzled what it meant.