Intrepid,
I was going to go out in the morning and brush the snow off of my old, twisted up fender to count the holes and perhaps take a picture, then remembered that I had recently seen an old photo or two of my 38 Elgin before it got wrecked in a truck fire along with a 39 Elgin, sidecar and a winter's worth of other bike projects.
I had bought the 38 on Ebay for a really good price and wanted it mostly for cool parts, although I thought about just putting a China girl motor on it and leaving it be as it had nice paint yet... considering it's age was in very good condition. Rode well, too.
I took these pictures to record other things for myself, but a couple of them also show the rear fender. The little hook deal at the fender holes suggest that a single piece of string, wire, yarn or whatever was laced through in a back and forth pattern to the hub plate.
The plate affair under the seat was an idea I had for making a mount for a behind the seat gas tank. It wasn't done yet, but I had finished the gas tank made from a juice can and covered in hand stitched harness leather I had left over from the time I raised Indian ponies a long time ago. It would have worked nicely, I think. I still have that plate, salvaged the seat and rebuilt it, salvaged the cool chain guard and that's about it. Still have the gas tank, I think.
I hope the photos are helpful and will try to get a measurement of the spacing between fender holes in the morning.
SB