Cylinder Head / Timing Chain

I am currently replacing a cracked cylinder head on a 1987 B2600 4WD pickup. This is a model with a timing chain. In removing the head we found it difficult to get the water pump and timing chain cover off so as to remove the timing chain. So, I levered it off the upper sprocket just as if I was taking a tire off a bicycle wheel. Although I did a good job of marking where the chain matches the sprocket, I am unsure about where the dowel pin on the back of the sprocket needs to be in space (ie 12o'clock or 1 or 6, etc...). This pin goes into the cam in only one way.

I think I have it at Top Dead Center and the chain is back on with the pin on the back of the sprocket/cam connection at 12. Is this right?

The second question is really messy. I over torqued and broke off one of two cylinder head-to-timing-chain case bolts. This area of the head is in front of the combustion area of the head. Please somebody tell me I don't have to remove the head and get this bolt out in order to replace it. My thought was that those bolts are there only to keep oil from slinging off the timing chain and out of the head. For one thing they are much smaller than regular head bolts and call for only 11-15 foot pounds of torque. Does anybody have any thoughts? Thanks, John in Corvallis