Yes, seems to be.
A quick test…
Save the current OPRA preset as a named EQ.
Then switch to a null MUSE, i.e. nothing enabled, and load the saved named EQ under Parametric EQ.
As you enable and disable PEQ, with this saved EQ, there’s a definite change in volume.
edit: oh, and even easier, just load the saved EQ, and click on the RHS “global” volume slider, which shows its default position is -6.3dB (in my case), which is the overall pre-gain for my OPRA preset.