I have written TWO articles on manufacturing dates and date codes on parts used on 356's.  The first is an article I wrote on manufacturing dates and date codes which should help explain the pictures below.  The article was published in the 356 Registry magazine, Volume 31, Number 5, January 2008.  In the September/October 2010 Registry magazine I wrote a new article that is specific to the date codes on Miss June.  Here are the two articles in PDF format.

First article              Second article (Miss June)

The pictures in the article on Miss June are a little hard to see.  I have put them below for better reference.  The explanation of the photos is in the article.

404 stamp on generator means April of 1964                                 403 stamp on the starter motor- March '64

405 stamp on voltage regulator- May '64                               A15 stamp on the Hella flasher means 15th week of '64

A27 stamp on Hella headlight- 27th week of 1964

405 date code on the bottom of the coil- May of 1964

It took me the longest time to find the date stamp on my distributor, which is the stock 022.  Finally, with the distributor out of the car, I found it!  In the top picture of the distributor above it is barely visible.  Look just below the retaining clip for the top, and slightly to the left.  The picture on the left shows a close up of the distributor.  The number is 405, which is of course, May of 1964.  Definitely original to Miss June.  Note that on the picture to the right, where I moved the camera back just a little, and the marks are virtually invisible.  These are darn small numbers, and not stamped deep into the casting.

Condenser

Bosch Horns- 406 Date code = June of 1964

All 5 wheels have the same date.

Oil Temperature sender

Below is a shot of one of the seat hinges. 

Radio serial number

Hood hinge

Doors

Carbs

Air filter canisters

Window Regulators

Fan Belt

Shocks