Well, as it turned out...
Those inserts were easily removed: I simply stuck a smallish screwdriver through the opening on top a gave a slight tap; they both popped right out:
Removed the old wires; after flux, tinning (using Marklin wire), here it is:
This is at about 10V off a Lionel Type S; the lights look much brighter in the photo. They are actually a nice, warm yellow. 
Still have to figure out the best way to get the two sides to connect together; until then the little rubber band will have to do! 
Mark in Oregon
