The serial numbers do not reflect this change - Fender continued to make instruments using existing serial number schemes.The new Fender did not acquire any physical assets of the old company, just the name "Fender".
Hence during 1985 to 1987, production of Fender guitars was only done in Japan, while USA Fender created a new factory in California. BUT note that the "E" and "N" series does sometimes appear on "made in Japan" models. In any case, if it says "made in Japan", then it is... Fender has recently (in the last 20 years) introduced LOTS of different serial numbers schemes, depending on the country the Fender was made (USA, Mexico, Japan, Korea, etc). Sorry, since I do not collect new Fenders, I don't really keep track of these things.
The Japanese-made Fenders do have some slight serial number differences (typically a "J" serial number prefix). I believe this was a mistake on Fender's part using the same prefix for both U. Below are some examples of letter prefixes used in recent serial number schemes.
My necks dated jan 67 the mounting plate numbers are 1970 and on the back of the neck that mounts in the pocket there is a F with the number 71 under the bottom horizontal line of the F so I believe all these various parts used on a 1971 guitar could of been made over a 4 year period.
Their all in bins an employee grabs parts out of bins and assembles a guitar.
These models have the serial numbering and markings in the same location as Fender JV guitars, and were made only during the years 1983 to 1984. acronym for "MADE IN JAPAN" These models spanned the years from 1984 to 1997.