How do you remove reed block pins?

[saltyfries]

I have a 1969 merc 75 (7.5 hp). I'm installing new reed valves but they spring open when I tighten the stops, so I want to remove the dowel pins and lap the blocks on a surface plate. Can someone tell me how to remove the dowel pins? Do they go all the way through or are they installed from each side?

Thanks.