yes you are right. they manufactured these devices. and then they explorered some chips that runs at higher Mhz. and then they separated them.
after that they manufactured z1 PLUS with separated chips that running higher mhz.
Thats how it works. Also: If someone wants to overclock seriously, he would also ask for voltage control, not only frequency.
If the voltage regulation on these are the same as the PinIdea RR-210, there is no programmatic control available.