James,
I believe Joe mentions in his report that the found connector is of the one prong version. (as below) minus external threads.
https://www.surplussales.com/Images/Connectors/Microphone/cna-80-M1_1_lg.jpg
In his report, Joes says:
"The 80-Series connector was listed in Amphenol catalogs, parts distributor catalogs, and advertisements as a microphone connector." but the documentation he provides shows otherwise.
He says:
"The 91-Series was a deluxe model. It came with 3-or 4-prongs. The 80-Series was an intermediate model, with 1- or 2-prongs. The artifact is an example of the 1-prong variant of the 80-Series. The 75-Series was the entry level model, with 1-prong only."
Joe does not provide a photo of the prong end of the artifact but his Photo #15 appears to confirm that the artifact has a single prong. Jim Champion's statement that "a radio microphone connector needs three pins minimum - Mic, return(gnd), and PPT(push-to-talk)" is actually supported by the images in Joe's report.
Joe's Photo#5 is an image from a 1936 catalog advertising a three-prong connector as a "microphone connector." No series number is mentioned.
iIn Joe's Photo #19, the one and two-prong Series 80 connectors are labeled "contact connectors." The three and four-prong Series 91 versions are shown separately as "microphone connectors."
Unless Joe can produce documentation showing a single-prong Amphenol connector marketed as "microphone connector" it is safe to conclude that he has misidentified the artifact. It is a "contact connector" and not associated with a radio, aircraft or otherwise.