Sharp eyes, there, Nev. You're correct, the Packard diesel was long ago scrapped and a buyer from Argentina fitted a Wright Whirlwind. That engine was lost along the way and the engineless airframe sold back to a buyer in the U.S. in 1989. That owner passed away before any restoration work could be carried out, and the sad remains of the aircraft only just escaped being dumped.
Another American purchaser bought the remains and rebuilt the aircraft completely and fitted a Wright R-975.
I have seen photos of complete Packard DR-980 aircraft diesel radials, some have survived, but it appears none are fitted to aircraft.
https://airandspace.si.edu/collection-objects/packard-dr-980-radial-9-engine/nasm_A19710893000