yes you can still shoot 3" through a barrel chambered for 3 1/2". its no different than shooting 2 3/4" through a 3" chamber. however, i know you said you dont shoot 3 1/2" but just for clarification, you will not be able to 3 1/2" shells even though the barrel can handle them your ejection port is only big enough for 3"
short answer yes the barrel will work just fine, order it if thats what you want and have fun patterning your new barrel when it arrives