Please see pg 26 of https://www.nyse.com/publicdocs/nyse/data/Daily_TAQ_Client_Spec_v3.3.pdf "However, if a quote sets both the National Best Bid and the National Best Offer, that quote is not included in the Daily TAQ NBBO file. These records are found in the TAQ Daily Quote file where the NBBO Indicator is “G” for CTA securities (src = “C”) or the NASD Indicator is “4” for UTP securities (src = “N”)." We also follow these same rules. This way we can use TAQ as our reference when doing daily sanity checks against our packet captures / parses. We will eventually have BBO data available on the platform - this requires us to go back and re-process all packet captures and add in QA steps well. I do not have an exact date on this, but will announce when I do. I hope this answers your question.
No problem, Quinton. Polygon data has a lot of good things to it --- both exch/finra and SIP timestamps (to nano sec), sequence Id, etc. All these are good stuff.