The weapons displayed April 15 appear to be a mishmash of liquid-fuel and solid-fuel components that could never fly together.

Undulating casings on the missiles suggest the metal is too thin to withstand flight. Each missile was slightly different from the others, even though all were supposedly the same make. They do not even fit the launchers they were carried on.

“There is no doubt that these missiles were mock-ups,” Markus Schiller and Robert Schmucker, of Germany’s Schmucker Technologie, wrote in a paper posted recently on the website Armscontrolwonk.com that listed those discrepancies. “It remains unknown if they were designed this way to confuse foreign analysts, or if the designers simply did some sloppy work.”