When CNC machining is done there often has to be a way to hold/align pieces to the work surface.
The tooling holes can be pre-drilled in the raw stock, set over alignment pins, and clamped to the table.
As I'm sure you've noticed, there are many "tooling" holes in the RAF. It is very important to locate the holes where they do not compromise structure.
I agree Harry. My memory is vaque, but I believe most of the tooling holes on the RAF are .190 or so.
One thing that needs to be said though is that I am unfamiliar with any failures of this part. Is it not the PSRU rear support bracket?
Another comment: The machining on the RAF is very well executed in my opinion. The engine frame, axle tube mounting brackets, etc. are almost works of art.
I suspect that whoever did the detail design on the RAF 2000 was a CAD/CAM guru.
The part looks used. The paint has been worn off around the hole, it looks like something was tied to it (saety wire?) instead of a bolt being in it. Is there a spring that hooks into the hole?