George,
You are correct. The main Belgian ports were probably stuffed with German vessals that were neatly impounded after the Germans surrendered.
About DWM's testing abilities:
Here is a very rare picture of a K98 being measured at DWM (somewhere between the wars).
<a href="http://forums.lugerforum.com/lfupload/measuringk98dwm1939.jpg" target="_fullview"><img src="http://forums.lugerforum.com/lfupload/measuringk98dwm1939.jpg" width="400" alt="Click for fullsize image" /></a>