I am not sure about getting certified copies. I know that you can check with the Pa Archives in Harrisburg. I have not gotten far enough to do the certification thing. One of my grandfathers was Philip and I know that he was in the Rev War. I contacted the DAR and they did confirm that for me but I still have not gotten anything together to send to join the DAR. The Goshenhoppen registers are on rootsweb and also in Ancestry. If I were you my first step would be to check with the archives. Very nice people there and they may be able to point you in the right direction.