knock pins

I've can't seem to find a clear answer on these little dowels that line up the cylinders. I have six after disassembling the engine. My question is, do any of these dowels need an o-ring to properly reassemble the engine on a 1972 CB350? This is my first post, but i've spent countless hours...

Well, I thought I was all ready to try to start my engine (sl350 k2) after finally getting everything back together. However, when organizing one of the tables I used for part of the assembly process I found two knock pins. I am positive that I didn't forget to put all the pins back in and...