I did not mean it as proof, but evidence it is, -- here is at least one apostolic Church doing it, and I am not aware of the daily Mass being any kind of Latin innovation. As Agrarian noted, the early Church had a much closer association between meal and Mass, so it would be reasonable to conjecture that it was.
As you say, that is a reasonable conjecture, not proof. Whatever form the early Christian worship service took, we simply don't know all the details. I think it reasonable that there was some variety of practice from one local church to another.