The .35 Auto is an oddball caliber, and I believe there were no other pistols from any manufacturer made for it. The .32 ACP cartridge is very close dimensionally, close enough that it will work OK in your pistol. I have done that, back when I had a sizable collection of American pocket pistols. It has been postulated that most owners of that pistol fired .32 ACP in it. I would just hang onto that partial box, it’s fairly unusual. Bullets appear to be FMJ, but actually they are metal capped.