The lowering bones (often called dog bones) lower your bike by changing the angle of the rear softail style frame, like the one found on 85 and up Harley softail models and later copies from the Japanese, like the C50, C90, M50, and others. On bikes with a conventional swing arm, like a Harley Dyna or touring model, or Japanese bikes like the S50, S83, and Honda VTX line, you lower the rear by putting on shorter shocks.
The C50/ M50 semi-sisters have a different engine, frame, suspension- basically a different everything- from the S50. So forwards from one will not fit the other. Too bad- it would make things a lot easier if Suzuki parts interchanged from model to model more.