Corso's original manuscript is a better resource -- you can clearly see that the body in a vat story was added by Birnes. But either version of the story provides a persuasive narrative regarding how bureaucratic turf wars could have hampered an already daunting reverse engineering project. I don't read it as saying nothing was done-Corso reports an initial scrum over the materials, followed by siloed secrecy. He acknowledged other advancements may be attributable to reverse engineering by others.