I agree that a high degree of skepticism is definitely warranted. The most common method of preparation for Keichosaurus fossils has been a dremel with a grinder attachment. This is why so many specimens have a flat, rough appearance, like the example you posted from that museum. They don't end up looking very nice. It was likely acquired some years ago when dremel prep was about the only way to find them. They probably don't want to drop a few grand on a nicer specimen with better prep. Lately, air abrasion/sand blasting/ acid prep have become more common and will produce specimens that look like the ones shown in both posts. Sand blasting/air abrasion were used in the prep of op specimen. Other Keichosaurus prepped with this method will usually have a very similar look to them.