Under existing California law, the only frame sticker that counts is the manufacturer's.
My 500W Canadian commuter with thumb throttle was configured and sold as a Class 2 in 2022. No manufacturer's class sticker.
And none would have made sense, as you can easily change its max assisted speed while pedaling to up to 36 mph right on the display with a readily available passcode.
The throttle's 20 mph max can't be changed, as required by Class 2 law. But that 36 mph takes the bike totally outside the class system. Hence, not really a legal ebike.
Ebikes with similar capabilities were already widely available in 2022. As were ebikes sold and even officially stickered as "Class 3" but equipped with throttles. Legally, Class 3 is pedal assist only. Hand throttles are allowed only in Class 2.
When I asked my dealer what would would happen if I were caught riding in a place with Class 1 access only, he said (a) that there are few places like that here in coastal SoCal, and (b) that if I ride responsibly, the odds of getting stopped anywhere are slim. But he had no idea what would happen if I
did get stopped.
So here we have both dealers and manufacturers either (a) freely selling clearly non-compliant bikes as legal ebikes to unwitting customers, or (b) telling witting customers that they're unlikely to face consequences. And that behavior widely extended to e-motos far removed from any definition of a legal ebike.
I was new to ebikes at the time (2022) and didn't understand the implications. Now I see that manufacturers and dealers were at the vanguard of the "ebike laws don't matter" mentality so prevalent today.
And now we're facing wildly over-regulating backlashes from alarmed citizens and lawmakers all over the country. IMO, totally preventable if the "ebike" industry had just stayed within the law to begin with. The auto industry generally does, and they still manage to make money.
This is why we can't have nice things.