The owner says this board is running RouterOS; can anyone identify the make & model? (The radio looks like an r52.)

That is an old 233MHz "PC Engines Wrap.2e"
http://www.pcengines.ch/wrap2e3.htm

It is an x86, so it can run Mikrotik just like a normal PC would.

There is a CompactFlash card on the bottom (the old flash card style, that works like a hard drive and holds the files and operating system).

Thanks! I'll pass it on to the owner.