Hello nor,
this may not sound correct.The 2000 figour may just be a sum rounded in saying & only that with no exactness.More seriosly though as you say,some people may have thoughtlesly forgot to sign or otherwise unintentionally not signed.Some time ago I remember ringing imf enquiring over the class action case & a progress report.At the same time I was told that we had signed. Imf would surely clarify this important issue...........