643 is not a loaded model, 636 probably comes with furniture and fixtures. Richmond American managed to find a buyer who paid 670k for 826 Luminara (another one of its models), which is substantially smaller. Also, it’s hard to explain the listing price increase from 750k to 799k just before the house went into escrow.
The deed is #2009-0520784 from Richmond American to Harold and Paula Vickery.
