Without seeing it, I cant say exactly what you need. The image in the link I posted should be all you need to figure out whats needed. If the valve cover is cut, you wont be able to fully seal the timing belt without replacing the valve cover itself, in addition to adding the plastics youre missing.
Since you have the lower portion, you dont need to worry about #1 and #4.
The top section is two pieces, an inner that goes behind the cams, and the outer that covers the timing belt. If you have the inner portion, that goes being the cam gears (#7) then all you should need are #3, #8 and 2x #19.