The dowels should press in pretty easily. When they get all rusty from coolant they don't work so good. The plus side is that they are cheap, and available at any parts store that sells Felpro. However, most parts guys don't know how to look them up. Tell them you need a Felpro ES 70744, which is a set of 4, and should run you around $4.
To John Dirks, there are two reasons you would see a clean piston like that. In this case, the OP has most likely cleaned it off to get a better look at the damage. If you pull a cylinder head and you happen to find a piston that clean it is caused by a blown head gasket. Cooling water seeps into the combustion chamber and essentially steam cleans the piston when it evaporates.
I just checked on the intake gasket. I'm pretty sure those are not reusable gaskets.
Kurt
To John Dirks, there are two reasons you would see a clean piston like that. In this case, the OP has most likely cleaned it off to get a better look at the damage. If you pull a cylinder head and you happen to find a piston that clean it is caused by a blown head gasket. Cooling water seeps into the combustion chamber and essentially steam cleans the piston when it evaporates.
I just checked on the intake gasket. I'm pretty sure those are not reusable gaskets.
Kurt