Late 60's Zenith B&W table set

[TUD1]

I got this set from Danny yesterday. It's just your basic no frills B&W tube table set. But despite its degraded state, amazingly it still produces a watchable picture. The tube is quite weak though. When you turn it off, you get a nice white dot for quite a while. I just got through cleaning it up which included cleaning the (yellowed) cabinet, putting DeOxit in all the controls and cleaning the tuner. Those really helped the picture. Before it was all grainy, but now it's nice and clear, just not bright. If I had a tube tester, I'd try rejuvenation, but I don't. I don't have an exact year, if someone could fill me in, I'd appreciate it.