That is indeed the oil pump drive shaft. The three "bolts" at the cam location are oil plugs. They don't need to come out to remove the cam. If the cam is stuck, make sure the oil pump drive shaft "sleeve" has come out on the oil pump. It is a small plastic or sometimes metal coupler that connect's the oil pump stub shaft to the oil pump drive shaft.
This one is metal and pinned to the shaft.
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Here the oil galley plugs are the pressed in type like freeze plugs. Most of them that I've seen are small pipe plugs with a square head.
I hope this helps, Jeff.