Could be that the person selling it doesn't know what round it is chambered for. If 9mm Largo is longer than 9x19 (Luger, Parabellum) and the headspace was checked for the 9x19, then of course it will be "excessive", even though there may be nothing wrong with it. Find out if it was checked properly if possible. If it wasn't, or if he doesn't know, offer the guy $50 for it as a wallhanger then call around to find a real smith who can check it.
I bought my FR-8 like that, the dealer said it was a nonshooter-display only. Asked him why, he said the headspace was bad "checked it myself". I don't know what gauges he used, but there sure weren't the right ones. I took it to a smith and he said it was the nicest one he had ever seen and it headspace checked fine.
bergie