If by REST you mean full on HATEOAS then I definitely would not use that as an interview test. Advocates tend to be religious in their intensity, yet few real world APIs are full REST in that sense. Discussions around HATEOAS could be enlightening but requiring people to buy into it not IMO.
I would structure interview questions around APIs rather about distributed systems/transactions, circuit breakers, etc. - practical aspects of running multiple systems talking to each other through pipes.