When i submitted my 485 appl I submitted a BC from the muncipality where I was born in India.Its not the copy of actual BC since I dont have it. They had my birth info in their 1970 year record. so they issued a BC on stamp paper saying "i was born ( with name ) on birth day as per our records" with my moms maiden name...inmy wife case I got non-availability certificate from her muncipality and 2 affidavits from her parents...her parents are now in singapore so the affidavit was attested by Indian consulate in Singapore.I guess i should not gettiong RFE right?