I don't know about Ford and Dodge, but Chevy didn't offer a 4x4 one ton dually until 1977. Even at that, sales of 4x4 models were slow...
In 1977 only 60,779 one ton trucks were made, and only 8% of them 4x4. That's 4,800 4wd 1 tons. Not many compared to 110,416 1/2 tons made that were 4wd, and 12,054 3/4 ton trucks that were 4wd.
In 1978 only 68,010 1 ton trucks were made, this, vs. 540,968 1/2 ton trucks, and 176,735 3/4 ton trucks. No percentages for 4wd models were given in the book I have for 1978.
Don't want to bore you all, just making a point that 4wd wasn't common on 1 ton models until later years. I had a friend that plowed in 1996 with a 95 Ford F-350 12' rack body, 2wd. In the middle of the winter, in the middle of a storm, he was out buying chains for it. He got tired of getting stuck. Needless to say in the spring, he traded it in on a 4wd rack body. He thought like most other landscapers, "I don't need 4wd" when he bought it, and maybe wanted to save on cost. WRONG. <B>You don't need it if you don't want to plow.</B> Yes, you could have a V box on the back, and ballast at all times. But who wants to increase fuel consumption, as well as wear on the truck, just to not get stuck?
~Chuck