From what I've seen, yes, the episodes are random; however, they'll usually stay in the same season for a period of time before switching; for example, it was a long time of me having Nick GaS before I finally saw a New York Schneider episode of "Make the Grade," but, once I did, they showed those for about two weeks before going to some Morris eps.
I know they do this with DD as well since they'll usually stay in, say, 1986 for a few weeks and then go to 1988 or to SSDD. Really, though, the only show they don't do this with is "Nick Arcade," which certainly does seem to be shown in a completely random order.
But, no, the shows are never run in order, although, with these little stints, they certainly seem to be!
Anthony