Indicia names
The major difference between the two Declassified titles is the indicia use of volume numbers. Although this second volume actually concluded publication after the third, the indicia specifically designates this title "Volume 2" and the other Queen & Country Declassified (2005) as "Volume 3".

A subtler indicia distinction comes down to what might be a typo. This volume is Queen & Country: Declassified, while volume 3 is the colon-less Queen & Country Declassified.

Cover titles
It is much easier to tell the two volumes apart by their covers. Volume 3 has the story title, Sons and Daughters emblazoned across each cover.

Number of issues cataloged: 5

Number of users with this title in their pull list: 2