Scott 3973 And 3974 - Non Denominated 39c Flag/Liberty Var.

I know I should probably trust the Scott Specialized Catalog for this, but I've been struggling to try and identify the varieties of the booklet version of Scott 3973 and 3974.

The 2011 Postal Service Guide to US Stamps suggests:
3973 = Die Cut 10.25 x 10.75
3974 = Die Cut 11.25 x 11

My 2011 Scott Specialized shows:
3973 = Die Cut 10.5 x 10.75
3974 = Die Cut 11.25 x 10.75

I know it's a very minor variance, but why should there be such a difference ... isn't the USPS Guide based on Scott's information on such things?

I can verify that the 2010 US/BNA Catalog by HE Harris lists 3973 as 10.25x10.75 and 3974 as 11.25x11. My Scott Catalogs conform to the same measurements as yours (10.5x10.75, 11.25x10.75).

Given the above data, I've been struggling to try and identify the booklet pane variety of these stamps and I've been spending way too long on it without success, so I thought I'd post them here:

I believe this one is a 3972, as it has no USPS microprinting:


The perfs on all three of these match, and all these DO INCLUDE the USPS microprinting. Through process of elimination they can't be Scott 3975 (as they are not die cut 8) and they can't be Scott 3972 or 3973 (as they include the USPS microprinting) so does that mean they must all be 3974's?

It seems to me there are minor variances on these examples, especially between the first two stamps. Note in particular the red and white of the flag behind the upper curve in the "S" of "USA" and the size of the sky background in the upper right corner of the stamps.





Are these variants or am I just flyspecking these examples too closely?

Any help will be appreciated. Thanks.

The blue sky above the date is larger on #3972 than on #3974. Also, #3972 will not glow under black light while #3974 will. I hope that helps - however very late I am to this post...

Maybe it'll help someone else someday.