Here is the frame in question:
https://www.glockstore.com/SS80-M-ModelI received one of these for a NIBIN entry and so far it has no markings except for "SS80" on either side of the grip and "MADE IN USA San Diego, CA" on the right side of the frame above the grip.
I called Glockstore, since it's the first search result no matter how many different ways I searched on Google for manufacturer or parent company of SS80, and got hold of one of their customer service reps. The customer service rep stated that SS80 is made by Polymer80, which is owned by them (at least that's what I understood).
Has anyone else heard this same information or heard anything different?
Any help is appreciated.
*UPDATE*
A very nice member got me to the classification letter they received from ATF and I got an email that was much more straight forward from their customer service people that both seem to support that "Glockstore" is the manufacturer.
Thanks to all the people who helped.