Sophia Krupa's Birth and Baptism Record

My great-grandmother, Sophia Krupa, immigrated to America in 1910 and married my great-grandfather, Michael Bodziony in November 1911.  According to her naturalization papers, she was born in Skrudzina, Poland, a small town that was, at the time of her birth (1888), part of Austria-Hungary.   When I first learned of her birthplace a couple of years ago, I went to FamilySearch.org to see if they had a microfilm that covered this geographic area and time frame.  I saw that they DID have microfilmed records for Skrudzina, but I did not order the film at the time because I had no time to go to my Family History Center and look through the reel.  So instead, I ordered a copy ofSophia's application for a Social Security number.  Since this form was filled out directly by Sophia herself, it's first hand knowledge of her birth date and parents' names.  On it, she lists her birth date as 30 Mar 1888, which is exactly the same birth date as what is listed on her naturalization documents.  Her parents are listed as Joseph Krupa and Katherine Mourdas.  

Fast forward to about six weeks ago.  Some of the birth records on the Skrudzina microfilm have been indexed and are now searchable on FamilySearch.  I find two Krupa families in Skrudzina that are having children around the time Sophia is born:

1.) Joseph Krupa and Catharina Czyrpak, House #16: Children born 1883, 1884, 1885 (none named Sophia)

2.) Paul Krupa and Sophia Hejmej, House #51: Children born 1886, 1890, 1892 (all boys)

So, there IS a Joseph and a Catharine there; Catharine's maiden name is different than what I was looking for, but no baby in 1888.  Apart from these families, there is one more 'Krupa' birth record from Skrudzina that I find in the index:

Indexed Baptism Record for Sophia Krupa, FamilySearch

The child's first name and birth date match exactly from what I have found in other sources.  Her mother's first name matches the Social Security application and her last name matches my great-grandmother's.  But no father listed.  I requested a copy of the record through FamilySearch's photoduplication service.  Here it is, record #4:

She was illegitimate and no father is listed.  Her mother was Catharina, daughter of Jacob Krupa and Mariae Kotodziej.  Also, Catharina lived in House #51, which is where Paul Krupa and Sophia Hejmej also lived at the time.  Paul and Sophia Krupa were likely related, but how?  And were there any other Krupas living in Skrudzina (other than those of child-bearing age)?  I need to order the microfilm and look through the whole thing carefully.

I did a quick search of Jacob Krupa and Mariae Kotodziej, and found six indexed baptism records for their children, ranging from 1843 to 1865.  However, none indicated the name of Catharina or Paul. The family lived in Obidza, Poland, which today is just a 20 minute drive from Skrudzina.  These records are on a different microfilm, so I have a feeling I'll be ordering that one, too.

Did Sophia live her life believing that her parents' true names were those she listed on the Social Security application?  Perhaps she was raised by the Joseph and Catharine Krupa in House #16 and she genuinely thought that they were her biological parents.  Or maybe she knew the complete truth.  That's probably something I'll never find out, but hopefully ordering these microfilms will help me learn more about her mother and the other families in Skrudzina and Obidza.