I found this .pdf pamphlet for the Feathered Dinosaurs
Exhibit, it contains a few photos of the Jehol
critters as well as some of Czerkas' models. Page
three has a photo of the Pterorhynchus holotype but
under, what appears to be UV lighting. You can see
much more of the skull bones and the dewlap. The
dewlap honestly looks more like a "feather" beard of
sorts than a pelican pouch. I don't know if this
photo was published in the book or not, I don't have
it and its not among any of the figures I've been
given. I wish I a had a larger version of it though.
http://www.dinosaur-museum.org/featheredinosaurs/exhibit.pdf