[T3] Shift coupler differences

[Soren Jacobsen]

Here's a mini mystery for you all.

The other day I stumbled upon the shift coupler that came out of my
October 1964 Variant.  It's unlike any of the late style VW shift
couplers I've seen.  This one has a solid pin going through it, which is
held in place by a clip that fits over a groove in the pin.  It looks to
be genuine VW.  Pictures:

http://blef.org/vw/t3/shiftcoupler1.jpg
http://blef.org/vw/t3/shiftcoupler2.jpg
http://blef.org/vw/t3/shiftcoupler3.jpg

Is this an early thing?  If so, when did they change to the more
familiar style?

Soren