tl dr - It absolutely matters.
All of these parts need to go back into the same spot in the same positions for two reasons:
- Sympathetic wear - Let's just say parts get used to each other. Once they have been meshed together for a long time, they are broke in together and work together. When you mix-n-match after the fact, unexpected wear can occur. Ultimately part failure is a distinct possibility.
- Along the lines of the first, but more important, is the valves are lapped to their seats so they seal properly. If you mix and match, the valves will not seat correctly. Some of them might, but most of them will not. You will lose power and you'll be tearing the engine back down to do it all over again. If you have mixed up the valves, you'll need to lap them.
Let me just say, keeping track of valve positions is a lot of work. Not keeping track of them is a great deal more.