US 1857 3c Washington - S.c. #26 Or #26A?

Classic Coins, Thanks again. With your help and a little other research, this relative "newbie" to more serious stamp collecting learned –
• Sort of knew, but verified:
o Scott numbers and Type have changed over the years and continue to change, i.e.:
o In the 1940 Scott catalog this stamp was listed as U.S. number 44; it's now number 26
o Even as being number 26 it's Type changed from II to III in 2008.
• Had no idea:
o What "plating" is or that it's a quite specialized area of stamp collecting
o That plate number and plate position is important and how they are determined.

This may sound so basic to you, but to a "learner" it's a real step up in the knowledge base.

The next questions are:
• Do I now try to identify and collect the other 197 stamps from plate 26? #128522;
• Further to this existing strip of 3, is the octagonal postmark, which appears to be from Philadelphia have any special significance? Maybe that's a question for another Post/String?

In any event this has been a great learning experience. Glad I'm retired and have time to do more. I've made a small donation to the site. Keep up the good work.

You're welcome, dongeej1010. It's nice to receive your feedback indicating that you've learned much here already.

I'm not aware of any significance to the octagonal Philadelphia postmark.

The resources for plating all positions of the 1851-57 imperforate issues are available online, but there are no comprehensive resources that I'm aware of (online or in print) for plating Scott #26. To say that attempting to reconstruct a #26 pane or plate would be a daunting challenge would be an understatement, in my opinion.

You should be able to download the 1942 edition of the Carroll Chase book, which covers both the imperforate and perforated 3-cent issues, for free at the U.S. Philatelic Classics Society site at this link:

https://www.uspcs.org/resource-cent...nic-library/

Try to read the Robert Hegland article on plate flaws in Chronicle 105. Lets see if I can get a direct link to it.

http://chronicle.uspcs.org/PDF/chro...05/17318.pdf