No. No it is not. The reprinting from the Duel Decks doesn't count as a Modern Legal printing.
Its timespiral timeshifted which although looks like the card frame, does allow it to be legal.
Never mind, I was incorrect. Did not realize that it had been reprinted in Time Spiral. My bad.
Even the TappedOut version of Browbeat has the purple "Timeshifted" symbol. Any card with the purple rarity is legal in Modern.