Win The War Stamps

hi there I was wondering if some one could help clarify the whole win the war stamp thing, I have looked on line and just seem to get more confused, do the rare purple ones always have a pre cancelled stamp on them , basically my husband has a collection from when he was young , he has two win the war 3c stamps with the eagle on, one is a darkish purple the other is the same but a lighter shade of purple ,
any help would be great
thanks

The Scott Specialized Catalog confirms that the rare ones (actually reddish violet in color), known as Scott 905b, are only found precanceled from either Los Angeles, CA or Fremont, OH.

Advance down to Scott 905 at this link to see the varieties. There are some shades of the common Scott 905 that are known, which have minimal value and should not be confused with the rare Scott 905b variety:

http://www.pnc3.com/primer/primer003.htm

WT1 -A most interesting and enlightening post. Though I do not collect US, I have several collections from boyhood and a large accumulation I will be going through shortly. Thanks again.

Wow...nice link

Great link, wt1. I spent some time there.

Do you mean this stamp?