http://www.cdegroot.com/blog/2007/04/18/squeak-relicensing-effort/
http://www.netjam.org/squeak/contributors/
As of 1 May it seems that there were still 121 sets of initials in the Squeak codebase whose associated contributions had yet to be signed over. That included a good few sets of initials which had not been (firmly?) identified with an author:
http://www.netjam.org/squeak/contributors/missingSignatories
So ...
why not take a quick look at the list and then take it from there if necessary?
Hey! I spot one:
ward WardCunningham
The alternative in cases like this is to presume they will not assign copyright, and rewrite their contributions. It is likely that half the folks on the missing list have only contributed a fix or two.