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.