Yes, random AR can be approved by center.
As far as AR off of published tracks in the NAS there are ways to coordinate with center to get approval for that kind of stuff. I'd recommend looking at the JO 7610.4 lots of good information, it is FOUO so you might have to go through your pubs shop or OGV to get it.
If you are lazy and can settle for the 90% solution filing to a track/anchor and requesting random once joined up usually is no problem.