Interesting, you learn something new every day in this hobby. I have not noticed 101 fenders with that chain recess skirted (or rather not cut out) before, but as always with Indian there is versions and variants.
I provide pictures for comparasion, pre-101 fenders with the front end straight down with the recess skirted, in comparasion to the 101 fenders that is a continous curve.
The picture with the blue background is mine, solid fender without hinge, pic taken from the wrong side but the chain recess cut out is visible. The green one without the toolbox recess on the opposite side is a Indian Four fender that has that skirted recess.
Brochures shows the early 101 Scout, with skirted recess and now is the task for club members to pinpoint the transition date when the factory started to cut out the chain recess and why!