We've been able to do a slight bit of preparation on a Maiasaura that was collected by TPI crews in 2004 from the upper Judith River Fm of Montana. Unfortunately no skin was discovered preserved in this jacket, however there were a few surprises.
The anterior 6 vertebrae show pathological neural spines, perhaps an old bite wound that healed. The chevrons (Y-shaped bones under the tail) are tiny, much smaller than what would normally be expected on a dukbill of this size.
This jacket contains 32 articulated caudal vertebrae in a string nearly 8 feet long. Strangely the chevrons are all nearly gone and the ossified ligaments normally found in ornithischian dinosaurs are completely missing.