Looking through the burnatonce.ini, I see these entries:
Decode MP3=-v %s --output=wave:%d -S --sample-rate=44100
Decode APE=%s %d -d
Decode OGG=%s -o %d
Decode FLAC=-d %s -o %d
Decode MPC=--wav %s %d
Decode AAC=%s -o %d
WaveGain=--radio --gain 3 --apply

Obviously I know all the decoders, but what I'd like to know is if the wavegain is active or if that's something I have to call somehow?

From the BAO help file, under Audio CD Mastering:

Other options are available by right-clicking the track list:

Apply WaveGain
Use the wavegain algorithm to equalise the perceived loudness of all tracks - useful for making compilations etc.

-C

Thanks. Figured It out.