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Levi's is not currently offering any 606 or 646 models at all. You would have to search 2nd-hand sites for those.
The Levi's raw denim models will have "Rigid" in the colorway name. Their current raw denim offerings include their:
Levi's also has one-wash models which can get high-contrast raw denim type of fades, which contain terms such as "Rinse", "Clean", "Crisp", and "Dark Hollow" as part of their colorway names. You can easily find those one-wash models by clicking on the darkest colorways on their websites.
Levi's also makes raw denim models which are not "Shrink-to-Fit", such as their "Rigid" colorway in:
And Levi's one-wash models, even though not raw denim, can still get high-contrast raw denim type of fades since they still have virtually all of the indigo dye left in them for fading.
Here is the Levi's product page for your 501 T model. There should be a "CW" date code on one of those waistband tags too which shows the date of manufacture at least.
The pics on that Levi's product page show that 501 T model is a one-wash, so it is technically not raw denim. But when new, that 501 T model still has almost all of the indigo dye still left in it, so it can still get the raw denim high-contrast type of fades.
And that 501 T is most likely made with a sanforized denim, which can come in raw denim form too. That 1967 505 in "Rigid" colorway is raw sanforized denim.
In Levi's non-LVC models, the only raw sanforized denim model they sell currently is their 517 model in the "Rigid" colorway.
And yes, sanforized denims shrink a ton (3%-5%) when washed and dried normally. I also always thought my Rustler jeans were "shrink-to-fit" since it was useless to try them on to see how they would fit in the store, since they did shrink so much when machine washed and dried.
Unsanforized denims, such as the 501 STFs, typically will shrink twice that much, 6%-10%.