Continuing the discussion from Librem is too expensive compared to Pinephones:
Nobody knows :). I assume that - yes. Because GPS is under direct control of a modem, and modem is a black box doing whatever it pleases. By turning it off in the android, you just tell android not to use it. It does not really affect GPS state itself, and modem’s firmware may still access GPS data and communicate it to the cellular provider.
But this is a pessimistic speculation. To be sure, one has to audit the firmware. Since such audit is impossible - firmware is closed - I go with my speculation - expect the worst, lest you be in for a nasty surprise.