Yes, your last link was what I was thinking of. It’s page ~16 of 2019 Q4 Letter:
https://ir.tesla.com/static-files/b3cf7f5e-546a-4a65-9888-c9...
Re:Q2 2020 Update
by contingencies on Thursday July 23, 2020 @05:33PM
(#23932528)
It appears to be the same process. Reading junk on the internet the main process innovation they appear to have made appears is large scale die casting to produce entire chassis frames in a single aluminium part. This - like most "innovations" - is less an innovation and more adopting a known process with different tradeoffs, increasing initial capital outlay to obtain enhanced production speed and a simplified production process.
In vehicle manufacturing process engineering, an interesting recent startup is UK brand 'Arrival' who decided to avoid stamped chassis parts entirely and instead assemble from sheet and extrusions (IIRC). They can allegedly assemble a whole van in a 1000m2 'microfactory' and have just brought out a bus concept. https://www.electrive.com/2020/03/20/arrival-moves-into-new-... https://www.pesmedia.com/arrival-bicester-electric-van-manuf... https://www.pesmedia.com/arrival-zero-emissions-bus-17062020... https://en.wikipedia.org/wiki/Arrival_(company) 3B valuation.
URL? I found a 2016 Fremont planned layout http://digital.olivesoftware.com/Olive/ODN/SanFranciscoChron... and a 2019 Fremont layout https://villanyautosok.hu/wp-content/uploads/2019/09/2019_09... plus GF4 images https://photos.google.com/share/AF1QipOVTM-avTBP0VMbqc3dynh6... No comparison of process flow, which would be very interesting. All I found was https://cdn.shopify.com/s/files/1/0173/8204/7844/articles/Te... which seems to have more to do with combining multiple buildings than altering process.