I'm undecided. The La-15 and MiG-15 were almost identical, except that one had a mod-wing and one a shoulder-wing. Given the number of mis-identifications we know happen in aerial combat (for example in another topic we learned how USN aviators mistook Zeros for Me-109s) I can well believe that pilots thought they saw something that wasn't.
Regardless of what whoever might have written on the web:
USN pilots was probably not teached enough about Messerschmitt 109 to mistake any plane in the Pacific for a 109 and especially not the radial engined Zero.
After a very short time Pacific USN pilots didn't know about much more than the Zero and the confusion must have been around the introduction of the Kawasaki KI-61, wich in fact used german V-12 engines and could resembles a 109 in the hurry :-|
Edited by Armand, 25 March 2016 - 02:30 PM.