Here are photos of the collection of debris that had collected in the heater box. The upside of having all the debris is it apparently absorbed all the antifreeze and none dripped inside the cab.
I'm a little disappointed that the original deluxe heater core was missing. That being said I'm sure getting the 2 inch core recored will be cheaper.
The amount of heat that the heater in this condition put out was pretty good. I guess it will be cooking me out of the cab with a new clean core.