For once I would have to disagree with OF (unless he was just yanking everyone's chain again)...turning the boards over would likely end up a huge disaster; if these are the typical oak floorboards used since the last half century, they are tongue-&-groove boards nailed tightly together beneath the surface, & the backsides are not flat nor are they finished...they have this molded groove down the middle to make sure they stay flat on the sub-floor even if they warp & cup a little...

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