2005 Kia Sorento Camshaft

Im not sure what discs you are talking about, but hey do use something similar to cap the opposing end of the head where the cam would go if the head was on the opposite side of the engine. Usually if it is in the engine, it needs to be put back in, they dont make any "extra" parts on the inside.

If they are external and you can access the cams, I would have to guess that you would have a huge oil leak if left off

You will need to time the entire engine. These timing marks should have been lined up before disassembly. I can post apic of the marks aligned, what size engine is it? Is it a DOHC or SOHC engine?

It can still be timed, but it will be difficult to get all of it lined up.When you move the crank, it can hit the valves, when you move just one cam in a head (say intake) they can make contact with the other valves (exhaust) this is why you should time the engine before disassembly.Here are the pics of how the marks should align. When the crank mark is aligned it is on TDC, you may want to back it off about 1/8 off mark, this should put the majority of the pistons down in the cylinders a little so as to HOPEFULLY not contact the valves when trying to align the marks. I would remove the cams from the head you did the gasket on as well, after the other side is tmed, you can always install the cams where they should be or at least very close.That way you dont have to worry about damaging anything on that head.If at any time you are rotating a cam and it stops, DO NOT force it, it may be making contact with something