Definitely the 3.58 oscillator, the burst amp, and all the RF-IF tubes will have shields, and sometimes others depending if the engineers put them close to sources of interference. BTW: In a CTC-4, all you have to do is turn a shield can a degree or two and the entire TV is thrown out of alignment!
But as far as a hum bar, I don't see a missing shield can being the cause. But who knows?
Charles