Not Priority Date
Since immigrant visas (greencards) are now available for all nationalities, priority dates are not relevant. Most service centers processed based on Receipt Dates of your I-485.
Will it help to do FP earlier? Only Texas is known to process based on when your FP is done. Several people did not get FP notice after more than 18 months from their receipt date. There are however, some applicants who got their FP notices much earlier. Coincidentally, their I-485s had also been approved earlier.