That would have .0078" of clearance on the bolt. A bit sloppy, but probably normal for a non ball bearing style pully.
I didn't see the rest of the attachments initially.
The 5.2mm is for the hole in the bracket. That sounds appropriate for a bolt to slip through.
Scaling the drawing with a known dimension, I come up with 46mm diameter.
You mention 45mm OD I believe for inboard pulleys. This is quite close.
Scaling again for width, I come up with 7.5mm and a 5mm groove width.
Does this jive with your research?
I would have thought skinflint AHGF would have used the same size pulleys everywhere.
It is looking like that is not the case.