If I recall correctly it used to bring all the stems in as stereo but now they are all mono, I think they will get it fixed to have mono if mono and stereo if stereo.
If you drag the source stems into Reaper you will see what's what.

If you use the above BB Drums script in Reaper it will give full editing control of all the sections rather than a single consolidated wav that you can't edit.
You can edit the stereo track how you like then convert it to stems with one click giving you the same sections as the edited stereo drums track.

I don't know if they have added the shots, holds n pushes to the stems yet ???