Possible wrong birth name preventing reunion?

Hello everyone and thank you in advance for any responses I get and I apologize for the long post. My father was adopted in May of 1966 (closed adoption of course). We have little to no info as the story my adoptive grandmother was given by the county social worker, I have researched, and found to be false (both parent died in a car accident shortly after childs birth, child survived accident). There are no records to support two people with his last name at birth passing in a car accident in three surrounding counties and I went back three years from his adoption date, so that's obviously false. Also he was given a birthdate one year and 10 days before his adoption date, my grandmother told us he was around 5 months old when he came to their home. We still have the clothing he was wearing and its consistant with a 5-7 month old child (I actually wore the outfit at that age). Again, inconsistancies in the story, his birthday as we know it is most likely false. We were also told that my father was adopted from a private agency in a city one county over from us, we found the adoption paperwork that inicated he was a foster child of the county he grew up in, not one county over and a private agency. Again, more inconsistancies. We have found a local family where a woman had given up a child with the same last name at birth 6 months prior to my father's adoption date in the same county. It was your average coherst and aggressive adoption on the counties part, unwed mother, illegitmate child in the social workers eyes as we have been told by her sisters. The mother has since past this year so we cannot contact her, however we were told by her sisters she did not get along well with the social worker. We have spoken to the family who said she was looking for the child for nearly 30 years with no luck, she had registered with the state and come up with nothing. Her childs first and middle names were Edward Wayne. My fathers first and middle names on the adoption paperwork were Randall William, but the last name is the same. There is very strong facial and build resemblance between my father, myself and this family. Everything lines up except for the first names. We even found the name of the social worker that handled my fathers adoption and the same social worker that handled this womans child, handled my fathers adoption. This is a very small county and the chances of two children in this time period, with the same features and same last name given up for adoption using the same social worker is slim to none. My father had registered with the state, but it can take years to get identifying information, if ever. So it would make sense that a link could never be made due to the difference in the first name. The only possibility is that the hospital or more likely in my mind, the social worker changed the first name, because the mother (as I am told by the sisters) immediatelly wanted her child back and it would help ensure contact was never made. My question to anyone here is (before I contact the biological father for a DNA test request) is has anyone ever seen this type of tampering with info before? Is this something that could even happen back then? It would seem to me there would be a red flag raised if someone changed the name of the child. Again, thanks for any input.