My vin is in the 20,XXX range and I have the new front/back seats. I haven't noticed any issues with wind noise, but I'm not sure what it sounded like before. I would bet that most/all cars being delivered now are on the latest hardware.
tesla has also said they are not building cars in vin order - so while it is very likely that every newly built car will have the latest updates, it could have an 'older' vin number
ETA: we all should be happy Tesla does use somewhat sequential VINs though and is pretty open with their information... my current car was built on a line that shared VINs between three model/brands (all Kappas: PontiacSolstice, SaturnSky, Opel GT) and reset the sequence each year. So there is no way to know, at least no easy way, where your VIN was within that model's production. Mine ends in 11000, but how many were specifically Solstice vs Sky or GT? How many were built per brand the prior years? no good (public) way of knowing besides vague comments from someone within quoted anonymously because they were not allowed to release the info publicly.