Nice radio!
I think you did okay on the price. Zeniths of this general type were very well made, and so there are still
a lot of them around. Depending on condition, they generally go for around $15-45, so you did alright, assuming no major problems once you receive it.
I picked up a K731 not long ago (like jeffhs's, but the more modern style with legs). This is the same model that my dad gave my mom for Christmas back in the early sixties, and has a lot of pleasant memories for me. It is in excellent original condition and plays beautifully. I'm in the process of re-capping it, and giving it a detailed cosmetic restoration. Also, I'm replacing the selenium rectifier with a silicone rectifier, something you should also consider, as they are a ticking time-bomb (or, ticking stink-bomb!
)
One thing you can do, re: rocknroll's warning about the hot chassis, is replace the original non-polarized plug with a polarized one. You just need to determine which of the two line-cord wires goes to the chassis, and wire that side to the neutral prong of the plug. Another good thing to do, if you plan on using the radio a lot is to install an in-line fuse on the hot side of the line (about 1/2 amp).
Congratulations!!
Paula