I'm new to the board and was intrigued by the thread and it's content. Authenitic? As others have said, Authentic is how momma or nonna made it.
With that being said, a lot changed as our ancestors came here from wherever as the ingredients changed; vegetables, milks, creams, meats, flours, etc. Most Italian pasta and pizza doughs are made with "00" flour... that wasn't found here (now it is in specialty markets) so all the basics changed out of necessity not out of want.
In Italy, depending on the region you're in, the food changes and when an Italian goes out to eat, they eat Italian but from a different region. If they are in Milano, then they'll eat Tuscan, Perugian, Puglian, etc which each one has it's own style and specialty dishes. In the north you find more brown sauces while in the south it's red. Why? It's what was available regionally. They didn't have trucks to send the stuff all over the country.
My heritage is Italian and German and my German grandmother used to make some peasant dishes I still remember (bad for the arteries but they were good!!) and yet no recipe in Germany exists for them. They were as mother taught her... in essence, authentic!;)
As for the sandwich... hailing from the Bronx.. it was a 'wedge'. I've often pondered that one as to how many different names there are for the same type sandwich... po'boy, grinder, hoagie, sub, wedge, torpedo and the list goes on...