Last summer we purchased and drank this bottle at Restaurant Les Cols in Olot, Catalonia. (Unfortunately, the bottle was not in wholly pristine condition–a little maderized and slightly bretty. But it was fascinating to follow in the glass, still with leathery notes and some fruit.) As it does not say Gran Reserva on the bottle, I wrote to the estate asking about its exact status and provenance.
Just about exactly one year later I received an email in return from Maria Lopez de Heredia herself, much to my delight. (As it has information that may be of interest to others, I post a portion of it here):
Yes, until 1981, all the wines where released as Crianza wines but the wine that you drunk was a Gran Reserva. In fact this particular vintage and label was only made for that client in San Sebastian. It was an special selection of my grand-father for them.
Very cool, if you ask me. I have kept the bottle and now will place next to it a copy of the email!