S4 Lens barrel screws and spacers

I recently received some 19 degree EDLT lens tubes and some of them had the screws with spacers on them to ride in the gap on top of the tube opposite from the focus knob on the bottom . I have never seen 19 degree tubes with the screws on top only 70 degrees. Are these screws necessary and if so where can I find the spacers?

Thanks for any help,