Actually, when I went to the library I was going to look up a Berks Co. book for your inquiry; however while I went on their computer which has "Ancestry Plus" - a library edition of ancestry.com, I found the information there. They made it look like there was a book called Misc. Records of ...Wildbahn. I thought there was a reference at the bottom of the page which said records were obtainable at a Family History Library. You can look atfamilysearch.org for "place name search" and enter Berks County or Reading. There's a long list of records.
I got the reference about the "Readinger Alder" (typo? or what they called it then?) and Rev. Wildbahn from partially reading this book:
The history of Trinity Lutheran Church, Reading, Pa., 1751-1894 Reading, Pa.: The Congregation, 1894, 299 pgs. Author: Jacob Fry
This book spoke of Wildbahn's extensive records and mentioned they were published in the Reading Alder.
Have you asked the PA State Archives? See the following:
"Although the State Library is not the custodian of any official or unofficial records such as birth, marriage, or death records, we can give you the information you need to search for those records. The collection includes compilations made from other sources, as well as an extensive collection of Pennsylvania newspapers."