Most of my non-AA experience on OW carriers is on IB. As a OW Sapphire, I never get good pre-assigned seats from Iberia and oftentimes am assigned a middle seat crammed somewhere in the plane when there are completely empty rows to be found all over. It is completely unpredictable and it is better to not expect anything from them based on your status alone before arriving to the airport.

You should have much better luck at check-in by showing your elite card and specifically requesting to change your seat to exit row if available or at least an aisle towards the front, etc. I suppose you could also try to call in a better seat assignment but my experience with those is that they don't always stick and you are given a different seat at check-in anyway.

Thank god they at least are finally posting IB seat maps at SeatGuru.com, etc. A few years ago, plane layouts on IB metal were a completely mystery to everyone.