The Official Collectors Guide is an outstanding book. John & Paul did an outstanding job. Considering the volume of info, a few errors seem almost impossible to avoid.

This book has saved me so much research time in the last three years. The value in priceless !!!

My take on either an addendum or revision is that there are no plans for one by John. If it's ever done, someone else is going to have to step up and take it on.