I did some searching online and saw on nearly every entry for Sylvester the same church listing as you mentioned in your original posting. I would guess the first person who posted that information online had it duplicated by others on their websites.
Since you are not from the area, I feel the best option would be to have somebody look at his birth/baptismal record at the York County Heritage Trust Library. They have index cards with individual records transcribed on them. If he is listed in a church record they have in their files, he should have a card there.
You can pay the Trust to do research for you, but for something so simple, you should be able to find a willing local person who will visit there to take a look for you.
It would be great if someone who reads this would have the record you seek, but if not, that is the path I would take.