Probably made by someone else for Reader's Digest, possibly an attempt to expand their offerings beyond their music LP boxed sets, which sold well for years. Never seen a pair, though; probably rare. Possibly a special offer to people subscribing to boxed-set series?
Any chance of getting pics of them? Maybe someone will recognize them as a re-badge or be able to guess who made them, from their appearance. If you buy them, pull the drivers out and post shots of the backs, or at least post any numbers written on them. Should be able to learn who made the drivers, at least.
My guess is that these could be decent vintage speakers. Probably not absolute top-end, but not bad, either. Their records are generally quite good quality; it seemed that quality mattered around RD. If the price is cheap enough, try them!