Thank you for posting your request on History Hub.
In regards to your request for a naturalization certificate, NARA does not hold copies of these certificates. USCIS is the only agency which holds copies of these documents. If you have already requested an index search of the record at USCIS, I might recommend requesting a copy of the complete file for your grandfather, as copies of the court generated documents as well as the Certificate of Naturalization should be included in his file.
In regards to conducting a search for court records, have you conducted a search for both federal records as well as state-level records? Historical records are often retained at federal and state archives, rather than at the court houses of the counties in which the persons being researched resided.
For federal record searched, I would advise reaching out to both our NY unit
as well as out Philadelphia unit
For State-level records, I would suggest reaching out to the NY State Archives
And also the Pennsylvania State Archives
I hope this is helpful in assisting your with your research.
what is the name? Date of birth? city of birth? year of immigration?
Give as much actual detail as you can so people can help and look.
You'll need to contact USCIS for a certified copy of first papers or second papers.
Depending on what the embassy will accept, him having only finished first papers in 1940 is pretty strong evidence that he was not yet a citizen.
You said you contacted USCIS-did you get a copy of his first papers or his A-File? the Alien Registration stuff in 1940 should've applied to him and would also be great proof.
Informal name changes or simplifications of either the first AND last name were common and often not recorded on paper, it is possible that there was a name change between his first papers and his second papers.
The World War 1 Draft card should say that he is an alien he likely registered for. (I think there was an alien registration push in 1917 for foreign males).
(also technically the census isn't a legal document and the person responding may not have given an accurate answer or may have been a neighbor, I wouldn't count on the embassy "trusting it" even if it is a really good source. Granted you can at least get an official copy from NARA-I would try at least asking the embassy via email if that would suffice to show he hadn't naturalized by that date).
If you had the date of his first papers and they might be here: https://www.familysearch.org/search/catalog/558485?availability=Family%20History%20Library
It is too much to search through unless you know the day/month/year though.
Have you paid for an index search if you don't know the C-File number of this person? Presuming there is a first papers that exists and is confirmed by USCIS, you should do an index search to get a copy of it as well as possibly the naturalization to show he hadn't naturalized before the birth of his son. So you need to go back to USCIS.