Yes. The classical equations we know and love for inverting gain and non-inverting gain still apply. The OP's circuit requirements just so happens to result in a special case, where the classical equations combine and reduce down to a form such that the gain is Rf/Rx for both inputs of the opamp, which, admittedly, looks odd at a glance, since the classical form for the gain of an non-inverting amp is A(1+Rf/Rx), not just Rf/Rx; where A is a factor calculated using all of the various other resistors in the circuit.