Yes you are right, in fact Gen 3 has released very few fire type Pokemon. Now let me list all the fire type Pokemon you can catch in sapphire..
Numel-Route 112, Fiery Path, Jagged Pass
Vulpix-You can catch him in the Mt. Pyre Grass
And those are the only fire types you can acquire in sapphire. Yes, only 4 you can catch in sapphire unless you count torchic but its apparent that you havent picked him for your starter.