Over the last few decades there have been massive improvements on telling which bones have attachment points for muscles and hints at how strong the muscles are likely to be, but it takes a long time to replace all of the existing artwork with newer and more accurate artwork.

Even with improvements to the muscle structure, any part of the body that has fatty buildup like breasts would be missed without soft tissues being preserved. I am fairly certain that a hippos nose and lip area wouldn't have enough detail to reconstruct accurately. Heck, tyrannosaurs most likely had lips to cover their teeth, but that is based on other animals with similar teeth all having lips to protect the teeth from dryness and rot that doesn't apply to crocodiles who live in a very wet environment.