Purpose of those "extra holes" in bolt-neck heels and pockets?

[Number Of The Priest]

Using two of my Jackson/Charvel bolt-neck guitars as illustrative examples, there appear to be extra holes that are clearly not involved in attaching the neck to the body. So what is the purpose of them?

2009 KE3 heel and pocket. There's a hole in the middle of the heel, filled with a little dowel-thing that is neither maple nor rosewood, but more closely resembling the alder of the neck pocket (judging by color). Looking at the neck pocket of the body, you can also see two small holes above the last digit of the date stamp.


1988 Model 1C heel. The hole is also in the centerline of the length of the neck, but this time shifted further towards the butt of the heel. And it isn't filled with a little dowel-thing. It's just a void.

[Rich#6]

The neck, isnt' that how they attached the truss rod?
The body, maybe so they can paint the body?

[freedom's door]

I always thought the ones in the body were for when they painted it.
Not sure about the neck.

[MPI]

IIRC, it's where they pump the mojo in

[Mudlark]

Yeah, I think painting for the body, but the neck? hmmm....

It would seem overkill to drill that big hole to simple hang necks on a rod for storage I'd think, but..? (pre-fretboard that is)
Perhaps it was used for attaching to a piece of equipment while being machined/sawed?

[AngelDeVille]

Reference point for the cnc machine.

[kamanda]

Yup, CNC for sure