Will the 2012 Jeep Wrangler have pentastar engine?

No, the 2012 Jeep Wrangler did not have the Pentastar engine. The Pentastar V6 was introduced in the Jeep Grand Cherokee in 2011, but it wasn't available in the Wrangler until the 2012 model year *refresh*. Therefore, early 2012 Wranglers would still have the older engines. Later in the 2012 model year, some Wranglers might have gotten the Pentastar, but it wasn't standard across the board for that year.