Not always, but often enough when Tesla announces something they also announce that it is in all the cars manufactured after a certain date, and that date is a few days in the past.
There are certain advanced bty features that are relatively easy to incorporate on existing production lines (Panasonic in GF1+Japan, possibly LG Chem in S.Korea/China) such as cathode materials and electrolyte additives. These are the low hanging fruit of Jeff Dahn's research, and may indeed be incorporated relatively quickly to provide a 'million mile' battery to existing products like Model 3/Y. These recipes are mostly public domain already through a series of academic papers and Tesla bty patents (thoroughly discussed on '
The Limiting Factor' Youtube channel), now just waiting to go into production.
However, the more fundamental architecture changes required to allow faster charging plus cooler hi-pwr discharge (tabless cells), and also the large gains in energy density (Maxwell DBE) while also decreasing pack cost (cell-to-pack layout) will not be a simple 'drop-in' for existing bty lines.
These will require new manufacturing tech, and facilities. The tech is being developed now at Fremont with the 'Pilot Line' for batteries, likely enough to support Plaid S/X.
But mass manufacturing of this new tech (when its ready) will not arrive until the new Tesla 'terafactory' is built, so likely ~18 mths before we see the first product (likely Cybertruck and Semi).
The wildcard in this is CATL in Shanghai, who have been working with Tesla on developing new batteries since at least Fall 2019. There may be some new tech rolled out there, although I sincerely doubt Tesla reveals their full bty tech 'wish-list' in this 1st product with a Chinese partner.
I suspect Cybertruck will be literally alien technology, as in, it'll be designed to work on Mars and the Moon.
Cheers!