I'm open to suggestions, before emailing Vans, about what to do about this. The outermost seatbelt anchors' nuts do not have clearance, and are butting against the flanges of the F-705D bulkhead side channels. I was able to get the washers underneath the flanges while inserting the bolts. But the nuts themselves don't have any space to be tightened on - one of the hex flat sides is right up against the flange.