Those notches don't look "factory" to me.
If the washer offset was toward the middle (away from the angle strip, would they still be partially under the angle strip? On my '51 (with pre-drilled bed wood from Mar-K so I assume they were correct) the fat part of the offset washers is toward the front of the truck, and the washer edge is about 1" away from the angle strip. I don't know if the '46 beds (which are 2" narrower) would be the same. Hopefully someone with an original '46 can weigh in.
