I think this is a late kit that used pre-built Zenith modules, and the DIY aspect was mainly connecting them, unlike the pre-Zenith Heathkits where all the components had to be soldered to the boards. Is that what the manuals show?
Is that a totally rusted tuner/IF shield at lower left?
I wonder how long it was under water? At least it wasn't deep enough to implode the CRT.