if updating this now, then yes. it's really a stretch but its better than a flat value. Id like to urge you not to be too liberal with saying something is the only usable sale - the 535 was not even officially outdated yet when you suggested this, and even if it would have been - it happened a few days before the used sale; you should always check how it compares to other sales from that time if you are going to use such old sales, especially when other sales happened only a few days earlier.