Here is a list of some WAVE users.
I don't know, if they still own a WAVE. If you are a WAVE user as well, please mail me.

The serial numbers are made of:
Example: 9511000133

95........ :
The first two digits are the production year.

..11...... :
The next two digits are the week of the production year it was made.

....000133 :
And the last 6 digits are the actual production number of the WAVE. 6 digest would have last for 999,999 WAVE :-)

As you can see, you can tell the age of a WAVE as close as 1 week.