Fixed it. Many thx. Went to an appliance parts center and got the element, and read the part number off the old thermostat and found one at Sears Parts online.
Thermostat was fabulously expensive (over $200), but very hard to find. Everywhere else was asking around the same (excessive)...
One additional piece of data: on the wiring diagram for the oven (pasted to its back - picture below), the oven element is called out as 3000-Watts and 18-Ohms.
My GE range from 1963 (model J 463Y3WH) now has both ovens non-functional and I am hoping for your help to find parts or the range is a goner. The small left oven has a non-functioning thermostat and the right oven just burnt through its heating element (picture). I have include a ruler in the...