The Mets did wear them as their Los Mets jerseys this season, however that was it.
According to MLB, teams must finalize the next season's licensed, official on-field jerseys by May of the current season. So, by the time the Mets wore those awesome orange-on-blue jerseys last season (in August), which were so well received, it was too late to make them part of this year's rotation. However, from what I can gather, they did submit them this year and hope to wear them more frequently throughout next season.
Believe me, the Mets know fans loved that jersey, which was designed by the team’s equipment manager, Kevin Kierst, who told me last year that he hopes they become part of next year's regular rotation as well.
David Wright agrees, once telling me he thought the orange on blue (no black) color scheme was awesome, especially if they all wear blue spikes.