Pop the cover, look inside, can get a lot of info from doing that. I'm going to guess its a simple design, 15wpc or so using discrete outputs, 4700uf or so caps, 3 gang FM tuner. Should be halfway decent for a bedroom system or something if it sports that.
Don't rule out who might of built it, regardless of whatever the case says. I found a "Royal 2000" receiver, kind of cool cosmetics (weird amber colored dial when lit), seemed well enough built, turned out it was an Electrovoice built receiver of about 20-25wpc, never would guess it either, powerful sounding thing it is, in that wide open thrift store with its matching Royal speakers, that thing played darn loud and sounded good too.
Plus if its something decent on the inside these oddball things make nice little sleepers, conversation pieces and such. I try to find TOTL models from obscure manufacturers. You'll find the stuff built like you've never seen TOTL contract built stuff (Project One Mark 1500, sporting its coffee can sized torroidal tranny, 22000uf caps, weighing something like 54lbs, the MCS 3125 and Concept 16.5 come to mind...), to the super obscure custom stuff (Audiograph 2A100, so rare it may be the only one that exists), to the decent unknown contract built stuff like the Royal 2000.