Should infantry guns fire smoke?

[plloyd1010]

I am referring to, but not limiting myself, theses guns:


These weapons had smoke ammunition available to them, the Japanese 70mm even had an illumination round. Other "infantry" designated guns, such as the U.S. M3 105mm, are already indirect fire and are thus considered artillery with smoke and illumination ammunition.

Obviously these guns would need to be able to the hex they are trying obscure. I would also expect they would need to be able to see what they are trying obscure as well.