I have a few of those (exposed) Seattle rolls that I found in my parents’ fridge. I tried developing a snipped leader in HC-110 just to check it out, and as expected, remjet city.
IIRC,
SFW started out using 5247 and 5294 short ends, and the film had 'movie film' perforations.
Internet legend has it that later they used regular C-41 film (3M??) but still claimed it used a "proprietary process".
This SFW film has standard perforations, if that helps.