The internal construction of the Model F and Model M are completely different, as you will see as soon as you open it up.
The Model M was not intended to be serviced, so with the bolt mod you are basically cutting it apart, and bolting your wreckage back together by an artificial method.
The Model F can be taken apart and re-assembled without damage, it just isn't easy. And it is harder on the big ones than the small ones.
That was the reason for my "Model F Bolt-Modding Guide" mentioned below, but, unlike the Model M, it is not necessary.
In fact, the more practice I get with the clamps, the easier the "sliding force fit" has become for me. The last one I did, I used the original tabs and added just 2 bolts (between the "8" and "F8" and between the Enter and arrow keys) where the plate flexes the most. I now recommend trying to do it the original way before drilling, and cutting the tabs only as a last resort.
Having said that, once the board is apart, you have a great deal of flexibility with the keys. If you do my near-ANSI mod, I believe that you end up with one barrel and spring left over.
If you decide to unveil the 3-4 "secret" keys, you will need a couple of extra barrels and springs. I have a few extras but don't ask me for more than a couple. Model Ms have different springs and all the barrels are integral in one sheet, so forget about M parts.
And, of course, you will need the keys and accessories (including the barrel "chimney" insert sleeves for stabilizer pegs) that you want to change out.
Maybe this will get somebody excited about making some Model M keycaps! I particularly want:
Windows
Mute
Pause
And you will realize that a full range of "media keys" would be great, now that you have those lonely orphaned keys just sitting there!