Multi-stream, variable cycle point, low bypass ratio, turbofan engines are in consideration for future tactical aircraft. Such engine architectures aim to cycle between high-thrust and high-efficiency operation as required by the demands of the flight profile. Integration of the nozzles with the aircraft fuselage can introduce new design components including aft decks downstream of the nozzle exit. It is necessary to gain further insight into what effects of aft decks have on the noise radiated from dual-stream, rectangular jets. This work reports on a series of far-field acoustic measurements of dual-stream jets with and without aft decks to better understand the effects these features have on the radiated noise.