I know this is common and when I post it, the system will alert the WL people that a version has been posted.  But it looks exactly the same and there are about 10 of them listed w/4 digit ISBN#'s-none of which match this book.  I just think this is odd. 

When you post a book without an ISBN, PBS assigns a short ISBN.  It is a one time number for your book only. You cannot post again to that number, nor can you edit the information once you post it without an ISBN.  So be sure to add as much data as you can when you enter it.

The book I have has an ISBN#.  I don't know why there are 10 versions of it in PBS w/only 5digit ISBN#'s.  Well hopefully someone will answer the email that says there's a dif version of it posted. 

All of the other books could be book club editions, that do not always have ISBNs. Some do, some don't. I have more that don't than ones that do. If it says Book Club Edition, on the dustcover, I'm pretty sure to not find an ISBN on the book!

Mary, sorry I mis-understood your OP. 

There's also a thread in the Book Bazaar that you can note that you have such and such that some have WL. That threadf gets alot of results.