For starters, the Lionel parts webpage is down, probably due to volume of the weekend sale. I was going to check, but I think the white board is nothing more than a terminal board, replacing wire nuts. The black behind the white board appears to be a self adhesive foam insulator.
K-Line and Lionel's reverse boards had different color wires. The wires on the Lionel board are also heavier like shown in the above photos. I'm pretty sure that the Lionel by K-Line products used Lionel product reverse boards. In that case, it would be the red and black wires that go to the DC motors. You can check by turning the engine over and looking beneath the trucks. You should be able to see the color of the wires running to the truck mounted motors. On the Lionel engines I have of this DC motored variety, it is the red and black wires that go to the motors. The blue and brown are the center rail pickup and the ground from the wheels.
In this case, it'd be difficult to get the brown and blue wires back into that white terminal board. You might have to ditch that board and go with wire nuts on everything. K-Line, always trying to hold costs down on their starter products, used masking tape for a number of years.
