Annie,
It is my understanding that you can request a number from WBCCI, if it is not in use they will re issue it. Our AS has at least 2 and possibly 3 sets of PO numbers on it. The game plan, when we get ready for the WBCCI , I am going to ask for the last set of numbers that was on there in an attempt to hide some of the ugly. If you can find a member with the directory from the year that the numbers are from you will be able to determine the PO. Some of the elder long time members will have these directories. As far as I know WBBCI doesn't keep or hand out this information. All they will tell you is if the number is available or not.
Aaron