Cleaning up my DB, is this table from a WPMU plugin?

Hi guys,
Just doing a bit of housekeeping.

I have a few tables with either very little or no entries and I think they may be from a few plugins I have tried and no longer have.

Are these tables from a WPMUDEV plugin? I'm only running a single install but installed a few WPMU plugins before realising they didn't work.

am_actions
am_queue
am_schedule
wp_am_schedule

I think the 'am' may stand for 'auto message' which is the auto follow up emails plugin I think.
Am I right and can I delete these safely.
I don't use the plugin as it's a WPMU only plugin but I had tried it before realising.
Cheers
Ross