Most, if not all, of the algorithms have stereo components.

I would suggest recording in stereo and then if you don't want that stereo effect in the recording, simply mix both channels together equally for mono.

I find the stereo efx sound GREAT on my recording monitors but they don't always translate well to the mono output of my amp. I've taken to tweaking the efx for recording stereo and then separately for playing mono. 

But I'm a bass player and YMMV.