Head Removal Question

Hey guys...I got down to my block and found out I blew my head gasket between my #4 and #7 cylinders. Now that I am cleaning the gaskets off while my heads are at the machine shop getting looked over and possibly resurfaced, I have this plug by one of my bolt holes. On my passenger side I have it but not on my driver side. I just need to know if it is suppose to be in the head or block. Here is a picture

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You may have the plug still in the head on the drivers side. They stick. You can by the dowels at Autozone or Advanced. They can order if not in stock. Felpro makes them.
Item # ES70744 is around $10 for the set