International scholars of Jainism (Dundas, Ohira, Bronkhorst, Balcerowicz…) tend to agree that the early followers of Mahavira did not:
It seems clear that the early Jain ascetics were not totally strict vegetarians and that, like the Buddhists, they could accept meat as alms if an animal had not been specifically killed for them (Paul Dundas, The Jains)
I suppose this was the result of having to beg for alms, and it would last for centuries in South Asia. A thousand years after the Buddha, the Visuddhimagga (13.3) defines ‘food’ as either the meat & rice diet or the (forest ascetic’s) windfall fruit diet (sālimaṃsodanāhāro vā pavattaphalabhojano vā). Still no chance of vegetarian alms, it would seem…
The Sīha Sutta is often interpreted as the early Jains protesting the Buddha’s carnivorous ways, but what they actually say is that an animal was specifically killed for him. As if that was the line for them too…