I built one for a family friend back when I was in high school. Not sure of the model number, but it was one of the later ones which was essentially a Zenith "System 3" set. Most of the boards were preassembled and aligned, making the assembly work mostly mechanical. There was one board that you had to solder together, which was a dot/crosshatch generator used for the convergence setup. The set I built was a bare chassis, which was then installed into a wall opening as a custom install. Really classy stuff back in the early 80s.
I would have loved to build a "real" Heathkit TV, where you actually had to do all the work yourself. But I could never talk my folks into it when they were shopping for a new set.
I built a lot of other Heathkits, including my first real set of test gear around the same time. I am hoping that the latest attempt to revive the company actually comes to something, as they are sorely missed. It appears that some former employees are putting out feelers to gauge interest:
http://heathkit.com/survey/index.php/278489/lang-en