Here are some of the extras that will be on the R2, so I would imagine the R1 will be identical http://www.bbfc.co.uk/website/Classi...2?OpenDocument http://www.bbfc.co.uk/website/Classi...9?OpenDocument
According to the R2 DVD web site there is a Region 2 release of Once Upon A Time In America scheduled for June/July with commentary by Robert De Niro, Joe Pesci and James Woods. So I would think that a Region 1 release would be forthcoming. Link to the site...