I can confirm that after a day of looking, I have found a Rare Leg armor. There were two Decoherent Engrams, one gave me a garbage leg armor, but I was spared a second chance after I found in my mail 3 Blue Engrams and one was a leg armor and it happened to contain a rare leg armor. Anyways, to the guy who hasn't gotten rare boots, Ratchet, you just gotta keep on playing the game. See you somewhere in the Solar System.