I Think that you need leftside cover from earlier model where those hoses go and the hoses of course. they are return lines as far as I know.
Others may confirm perhaps, Im not 100% sure
the oil lines go from the crankcase to the cylinders
my concern is with the oiling to the heads
there are no external lines to the heads in either early or late 900 motors
so I am hoping the oil passages from the cylinders to the heads is the same
that is my question
Dan...........