Usually when layers move in different directions and slide over each other, the registration holes are put on the top and bottom. I've seen lots of set-ups where one layer had the holes (and sequence number) on top and the "moving layer" had both on the bottom. It's irritating when they are stored together, and the moving layer gets stuck out of position, as in this set-up:
http://sensei.rubberslug.com/gallery/in ... mID=206659 (note: major CCS plot spoiler included in description)
It illustrates the situation: Yue has registration holes on top, Eriol has them on the bottom. The Eriol layer was intended to creep up slowly during the cut (though sadly not as far as where it's now stuck).
The machines on which cels were photographed in fact had pegs where the registrations holes fit, and a set of cranks that allowed the layers to be moved at a regular pace, as during a pan or a "moving" shot against a background. In cases like these, the cranks moved separately. It looks from the screen grab that in your cel the little tyke would be catching up to the older woman on the other layer as they both walk. In that case, the layer with the older woman would have the holes on top.
As for the sequence number, it just looks like the person who pulled the layers out of the special photocopy machine that lays on the trace lines just made a mistake in labeling the layer, Then s/he carefully inked out the error and wrote the correct number after it. With the number of cels being prepared for painting, stuff like this happens more than you'd expect.
Hope this sheds some light on this issue.
I did have a dig around the AB forum for anythink on the topic first but empty handed without a clue.
Is this normal have the holes at the bottom of the cel?
Have no idea what is going on with the crossed out sequence number, can it be a mistake?
just a puzzle to me.
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Thankyou Cutiebunny, Sensei & Sylia for shredding more light on the topic