Well, that depends. The AMT "Movin' On" Kenworth is just the standard AMT kit with some Movin' On-ish decals. Depending on which truck you want to make, you have some work ahead of you. The AMT kit is a 1968-72, where the trucks in the TV show were a 1973 for the pilot & a 1974 VIT for the series. So, if you want an accurate "Movin' On" truck, then the kit has issues, but if you just want a nice looking W923 (spring suspension - W923, tandem torsion bar suspension - W925), then you have the right kit.
I built that kit last in 1984, and if I remember correctly it was a typical AMT kit - very little fits well without some work. As far as rare, well, all the AMT Kenworth W900 trucks are rare as the cab/hood molds were supposedly modified/destroyed to make the Kenworth T600 kit back in the 1990s.