I've not heard anything about Somewhere Now being released as a single or even the potential of releasing it as a single.
However, absolute radio have it listed underneath their new music section, and it's also overtaken Still Breathing as the most played Green Day song on Kerrang over the past 30 days.
Green Day have released different singles in the past outside of the US (East Jesus Nowhere being the last one I can think of) and this would potentially explain the reason for the de