As far as I can tell, (from 25 year old communications with Jose Penteado Vignoli in Sao Paulo, Brazil) the 1960-62 AeroWillys is the same car as the 1955 Willys Custom 4-door in the USA with these exceptions: all the Brazilians had the 161 F-head engine - this engine was upgraded a few years later to a dual carb intake manifold. All Brazilians had straight line side moldings rather than the zig zag of the USA cars. Brazilians had different interior fabrics and, I believe, hub caps, too. There may be other things, but that's all I'm aware of at this time.
For 1963, Brooks Stevens redid all the exterior sheet metal except the hood. The dash was also different on these later cars.