I got a response from Brimski. He confirmed that it is indeed a real Hummer's Giant. He mentions that he grows the cuttings under lower light conditions, which may allow better expression of the flared midrib. He also doses the plants with sulfer, oils, and other chemicals which causes the splotchy leaf burn and soil PH issues that might affect pitcher morphology. The plant I received was indeed very splotchy, so probably had quite a bit of chemical treatment.
Looking at more ceph pictures, it seems that for Hummer's Giant the size of the midrib is kind of variable, for example in these pictures of different plants from a different seller I see thinner midribs alongside wider ones. It also seems that the wider midrib are on the more mature pitchers with a pronounced "bean" curve.
I'll take Brimski's word for it since he seems very reputable. I think I'll chalk it up as to my plant not having any massive pitchers yet. There's a lot of growth points in a big clump, just no super big ones with an extreme curve to the bag portion yet. Me cutting up the plant into a bunch of cuttings probably didn't help
On a different note, I'm interested in what is your lighting conditions for your True/Fake Hummer's Giants? They seem very well colored, and that one dark fake one looks real nice. Also I'm interested in temperatures and the potting soil, as those may affect the coloration too.