U439f Blue Paper (Die 9) Varieties?

According to the Scott Catalog these examples should be U439f (obviously, blue paper) in Die 9 (based on the shape of the letters) but you can see obvious differences in the size of the lettering and the circles, as well as a distinctly different shade of blue on the envelopes. It also appears visually as though the top example is a "large head" and the bottom example a "small head" variety.

Are these varieties that are not mentioned in the Scott Catalog?

Not mentioned in the Scott Specialized, AND ...
not mentioned in the UPSS catalog. But it should be, IMHO.

There are lots of die varieties across the whole circular die spectrum, but most are hard to pick out. This one is like a roadside billboard.

Your top scan will have a large head (9.25mm, a la die 1), and the bottom will have a small head (8.75mm a la dies 5&6). Also, note the way the hair projects under the bust. Your top one will show the hair curling under and smoothly joining the bottom of the bust. The lower one has the hair curling under the bust and meeting the bottom of the bust at (essentially) a right angle.

I'm sure there are more differences. This area deserves study.

Compare the E's in CENTS.

I see that (the "E" in "CENTS")...but also look carefully at the "ED" in "UNITED" and the "ST" in "STATES" as those letters appear to have distinctly different spacing.

I hadn't focused on the spacing of lettering before. Very good. Thank you.

Again, variations in early and late working die condition is not appropriate for the catalog

Interesting opinion, especially since the catalogs do identify letter spacing and thicknesses as part of the means to identify other Dies for that issue.

Even if one were to discount those details, I would think the small head v. large head bust of George Washington would certainly qualify for at least some mention within the Die 9 reference.