Aef Booklet Pane 498f On Cover?

On Sep. 16, 1917, it was decided to change the APO numbers to the 700 series, because the American APO numbers and the French postal sectors were being confused with the British APO numbers. Mailly was initially 7 and changed to 707.
This cover still shows 7 in the cancel so either the cover was mailed before Sep. 1917, or the cancel number was not changed.
"booklet pane" is a little too much, 28 stamps are missing for the booklet pane :-)
But the cover and stamps looks ok to me, though I haven't seen many of those AEF stamps on cover...

I should have said booklet pane singles. I was so flustered trying to figure out how to navigate the site I bobbled the question. On cover individual stamps from AEF booklets scarce and difficult to ID, but the imperf top margin and close margins on other sides are diagnostic for singles from the top row of the AEF panes. Figured I'd get some opinions before sending it to the PF for a cert.

Wide top margin stamps usually come from positions W5, W6, W11 or W12.
While there are fake mint panes around, made from imperforated sheets, I've never even heard of someone faking an AEF letter with stamps. Too much work to get everything right, for too few collectors I'd guess. I'm pretty sure the cert will say genuine.