RickB: D'Oh!, I must admit that I only tried one round of .380 ACP in my .32 ACP mag. (I have a single round of .380 ACP in my reference collection.) It looks like a .380 round with a short ogive bullet might fit in the .32 ACP mags, but this would really crimp one's options for ammo.
Alas, I suppose this may just be a one-way conversion. However, I can't imagine why anyone would want to convert a M1908 to .32 ACP.