I need help with a Buick 248 straight 8

I have to change some bad exhaust gaskets on my 248 straight 8 and when I get the manifold out I see this. It seams like some sort of guide pins but I rather would like to see a bolt there. Is this the original stuff? First I thought that someone had break the bolt but then I see one like it in the middle exhaust port. Can somebody tell me if it’s supposed to be like that? Weird
Look at the pics

Thanks

 

I am in the process of doing the same thing on my 263. It has these same guides so it must be stock. I went ahead and replaced them with studs. I have not started the car yet so I can't say if it helps or hurts as far as leaks go.

 

Thanks for your answer, yeah that’s was my first thought too replacing them with real bolts.

 

Guide pins. I have them on mine with no issues. Really hard to get a bolt in that rear hole. On my 50 both manifolds have a flange on the side of the next bolt hole over. a long bolt and plate help to clamp them down.