[suicideneil]

Besides Mod1.0 vs Mod0.8 ( 32pitch ), I think the only major differences you will find are thickness of the gear in the middle vs outer edge with the teeth, and the mounting pattern. They either tend to be 'square' hole location patterns, or more oblong- imagine a square box in the middle of the spur with a hole in each corner, then an oblong box with holes in each corner. Thats a fairly easy thing to spot though so I dont think you'll have too many issues finding suitable spurs (famous last words).