Doing Vanguard Eagle, Viper, Wolf, or Tiger strikes will award blue engrams [b]at the end screen.[/b] The blues you obtain from the end screen can turn into old gear. In your case you would have to be awarded a class item engram and be lucky enough to turn it into one the two. Unlikely but possible. Just remember that the only blue engrams that can do this are the ones that are awarded at the end screen. Any engram you get from killing an enemy will not count.