rear defroster in 1969 valiant

1969 valiant that has been pretty much gutted on the inside. the rear package tray has a slit for a rear defroster but there is not vent. There is also no hose. Anyone have any idea what i should be looking for to see if this is something i can bring back to life or should i just buy a new package tray without the slit?? i can't find a switch for rear defroster anywhere in the cluster. There is an anolog clock where the manual says a button or switch would be. Like, how can i tell if the current defroster/air is something that would accommodate it? what hoses or connections should i be looking for?

thanks in advance.tray 2.jpg

tray.jpg