While I sadly did not take a picture of the museum label, from what I recall from close to 10 years ago when I took the picture is that this armor was from Mexico, and was parade in function. I could stand to be corrected on this.

This is a quandry!! Seems like there was some elaborate deity of worship through the Meso American history Olmec, Aztecs, Mayans which had the feathered serpent god Quetzalcoatl......possibly this was indeed a parade costume.
The notion of the feathering is compelling in suggestion to the lamellar armor we're looking at, but of course speculative as similar type of armor were in use in Europe in much earlier times.

Thanks very much for sharing the pics! Those adarga shields are REALLY hard to find, last one I saw was BAVIA and was in use in the Alamo context.

Jim, here is another adarga, currently exhibited in the Carmel Mission in Carmel, CA, which belonged to a soldier in Portola's expedition. It is interesting to see they were still used in the New World in the second half of the 18th century.