I485 Filling without Supplement J Employment Confirmation Letter

[Senmca]

My I140 approved under EB1C. Its has been filed by my current employer. I am planning to file I485. Due the recent visa bulletin released for April 2018, am planning to submit before 31st Mar 2018. However, I don't have supplement J "Employment Confirmation Letter" from my current employer. Its still in progress. I may get it in another two weeks. Would like to know whether non availability of the below documents leads to RFE or Denial of GC.

 1. 485 Supplement J (Employment Confirmation Letter)

 2. Birth Certificate or NABC not available

Whether i can go ahead and file without the above document or should i wait till Oct 2018. Please advise.