Humm... It's difficult to say.
These are from a /6. The port seems to be closer to the corner than the one you are showing, then again maybe not.
Click to view attachmentClick to view attachmentAnd this is a /4
Click to view attachmentedit: Same as rgalla9146's comment. Six seems to be closer to the corner. Nice valance BTW!
One things is sure, with the valance being curved, the hole isn't round. It would be nice to be able to have the pattern and a relation to the closest mounting point.