To/from SFO, their regular menu often features a vegetarian dish (pasta, not vegan). Not sure if it's always the case though. Also, if you don't preorder a veggie meal, the entrée (or starter for Americans) will not be vegetarian. And you may not have a vegetarian choice for the second pre-arrival meal.

I should add that I have had decent, correct Indian veggie meals with AVML, so you may be OK. I would suggest you go ahead and order AVML; the worse case scenario is that the main dish of the first meal may not be good, but at least everything else will be fine, and you may be able to get a vegetarian main if they have extras.