Did you mean 2010 instead of 1020? The 1010 and 2010 were built from 1960 to 1964 and they were not the greatest. They were replaced by the much bettert 1020 - 2020 design.
Yes, Waterloo and Dubuque were were seperate design groups. They may have even been in different divisions of the company.
A neighbor had an early 2010. He had many problems with it and didn't have much good to say about it. When the 2020 came out the dealer hauled a new 2020 and loader to his farm and asked him to try it for a few days. He like it and traded his 2010 for the 2020. After that he used that 2020 more than his JD 70. A number of neighbors bought 2020's after that, including dad. They were happy with them also.
The closed center hydraulics and wet brake systems can make new generation JD transmissions and hydraulics more expensive to repair today than other contemporary tractors, but they have run for 40 to 50 years without requireing much maintenace beyond transmission oil and filter changes and bleeding the brakes.
A hydraulic reverser or high-low shift may have been more troublesome than the std. 8 speed shuttle-shift transmission.