Amend a return after filing during extension, what is the SSN due date?

[bluered1b]

I have filed a timely extension which gave me until Oct 15, 2019 to file. The intent was to complete and file my return after I received my child’s SSN before Oct 15. However, some unforeseen circumstances will require me to file now prior to receiving my child’s SSN. I'm not able to wait on receiving the SSN to file now without it.
If I file now (during my extension window) without claiming my child (no SSN) then later I file an amendment (after couple months) after my child receives the SSN but prior to Oct 15, 2019, will I still be eligible to claim the child as a dependent?

My understanding is the child needs a SSN issued before the "due date", the confusion lies in what is the actual issued due date if I already have filed during my "extension" period?

Automatic Extension -> Filed without dependent -> file amendment once SSN is received

[DoninGA]

If the SS number for the child is issued before the due date of the extension you will be able to amend the filed return to add the child as a dependent.
See IRS Publication 972 Child Tax Credit - https://www.irs.gov/pub/irs-pdf/p972.pdf

[bluered1b]

Thanks, I did see publication 972 but I was still not clear if I had already filed during my extension if the due date used for the "issued" ssn would still fall on Oct 15.