Changing Manifolds

[flattie39]

I have a 69 C10 short/step with an inline 250. I'm in the process of swapping the original intake/exhaust manifolds for a 4bbl Offy intake and a 12 Bolt split exhaust manifold. At both ends of the head, there are pilot pins to hold the stock exhaust manifold in the proper position while bolting it in place. My question is: Are those two pins screwed into the head or pressed in? I don't want to risk breaking one off if they're pressed in. Thanks,
Ken