Hit by lightning?

[Kamakiri]

On the workbench yesterday was a forlorn GE model 516F, seen here:

http://www.radiomuseum.org/r/general_el_516f_516_f.html

After pulling the chassis, I noticed that one of the original .05 caps was internally charred badly, and crumbled like charcoal. Whatever caused this, the cap must have poured its contents out the one side forcibly, as there's a lot of fine gray powder under the chassis in a streak emanating from the capacitor. The rest of the caps were the usual blistered-looking wax originals. Replaced the rest of the caps, including the main electrolytic, but still have no power, going to test it further tonight.

I've never seen a capacitor look more like a blown roman candle. What the heck would have caused that, perhaps a lightning hit or a power surge?