No K-pins at all huh... yet Wildfire does use a K-pin related opcode. And it is used during the time when you'd expect sound(big hint!). Maybe that is for loading the digital-to-frequency converter, and the Fout pin is the freq.
wildfire.xcf: Too bad about the smudge. Can you see something looking like a mask programmable 7seg decoder? *edit* could you upload it as .jpg? MS Windows isn't very xcf friendly.