Hello, and thanks for the warm welcome 
As far as machining goes, it's a pretty volatile market as of late with old tech phasing out and new tech being difficult to attain, but the methods remain and knowledge helps clear the gaps.
I'd highly recommend learning some machining or woodwork techniques as it would make the coveted gasket mount cases etc a lot easier to make yourself 
I'm not familiar with that PCB, which holes do you mean?
I attached a picture of the 1upkeyboards 60% RGB Underglow PCB that i intend on using, but i've noticed the 6 holes (turns out i can't count) near the space bar switch pins are located on different parts of similar 60% boards so i figured they were probably for testing or could be for the end user to extend their keyboard (which would be wonderfully insightful)
I know it's hard to see, but unfortunately that's about the best quality photo i could find about it.
Cheers!
Yes, that makes sense. There's still a place for things like traditional mills and lathes though, right? I know they still use them in gunsmithing. I had to look up this gasket mount thing. I'm a clicky guy, I like my keyboards loud. lol
Interesting. I'm no PCB expert, but I have never seen something like that before. It doesn't even look like it is meant for a header.
This is the one I looked up when you mentioned it. I see that this one, instead, has a little momentary switch and resistor in the same area, on the reverse side of the board. Reset/bootloader button maybe? They look to be at least slightly different designs either way.

I would ask in the Keyboards section of the forum, or maybe the Making Stuff Together one. It gets a lot more traffic than this area, and would be more focused to the question. Maybe somebody that actually owns one of those boards can at least get some closer pictures of them.