The (1920's) Lower East Side locations were the Williamsburg Bridge on 8th Avenue South at Bedford Avenue, in Brooklyn.
Fat Moe's Bar was a set meticulously reproduced in Rome, modeled after the Lower East Side neighborhood.
The following is an exact quote from the movie production press kit:
"You could only have shot these scenes in New York," asserts Leone. But every inch of setting had to be measured and recorded so that it could be rebuilt for additional shooting at Pietralata, about 10 miles outside Rome, where the Williamsburg section of Brooklyn rose out of the anonymity of the Roman countryside, including two blocks of storefronts, an alleyway, and uninterrupted views down streets typical of the period, complete with fire hydrants, smoking water-main lids, even period mailboxes. Along the way, shop windows heralded such establishments as "Shaprio's Used Clothes," "Altman's Luggage"
and the eatery known as "Fat Moe's."Somebody prove me wrong and I'll buy the first 5 rounds.
Stephen Pelletier
www.onceuponatimeinamerica.com