Found a small dowel pin after flipping the head to clean the surface. We think it goes in the middle of the top of the head under the center cam cap and acts as an oil passage.. is that right? ITR head.

Also, whats the best way to prep the block and head to be rejoined? We used motor oil and 1500 grit paper.

 

Pic of that dowel/o-ring placement is in this thread:
https://honda-tech.com/zerothread?id=480870

If you're referring to the decks, I just wipe them down to make sure nothing can prop the head gasket up, and check them for straightness.

To me, hand sanding is too imperfect of a method for cleaning the decks. It'll only make a mess for you to clean up and won't correct deck straightness anyways. At best, it'll do nothing for you and at worst, it'll make the deck surface more uneven b/c of differences in grit as you wear it down and hand pressure. Maybe there's something I don't know about it, but it just seems logical.