What's always interested me most about this example is that Donald's dialogue as he flees, "Sir Quackly got him!!!!!" is obviously relettered by editor Carl Buettner; it's clearly Buettner's lettering style (compare with various wolf stories, 1945-46) and even with a bunch of exclamation points stuck on the end, it still doesn't fit in the voice balloon.
Since "done for" appears, unaltered, in Barks' own hand in the panel following, I suspect the relettered panel must have used the word "dead" ...and perhaps some more vaguely controversial information.
It's easy for me to imagine Donald saying something along the lines of "The poor dope's DEAD! Cold as a cucumber!" Seems to fit the voice balloon, though of course I have no idea what was really originally said.
That seems very plausible. I've always wondered about that panel. You never see Barks using FIVE exclamation points.