Gibson used to use Brazilian rosewood until importation of that wood was banned. They were also recently in hot water for using rosewood harvested (allegedly illegally) from Madagascar. I don't know how how that story played out but Gibson sure seems to have a target on their back from this current administration.
Lately they've been utilizing something called "Torrified maple" for their fretboards. It's dark brown like rosewood but hard like regular maple. Of course, many Gibson customers are "purists" who believe a Les Paul is a perfect combination of mahogany, maple, rosewood, neck angles, nitrocellulose finishes and even the glue that is used (when Gibson switched from hide glue to Franklin Titebond, hell broke loose!) and any deviation from this formula will produce a different instrument, lacking its signature tone.
In short, putting a Torrified maple fretboard on a Les Paul will undoubtedly result in mountains of angry letters from Gibson players!
Importation of Brazilian Rosewood was banned in 1992 until CITES (some exceptions to be discussed). It was and is considered the king of tonewoods for acoustic guitars, both because of its tonal qualities and the wonderful chocolate brown color with great swirling grain. All of those $200,000 -$500,000+ pre-war Martin D-28s that are considered the Stradivarius of acoustic guitars are Brazilian Rosewood with Adirondack Spruce tops (with forward-shifted bracing).
Again, although Gibson used some Brazilian Rosewood, Gibson's always been more into maple and mahogany acoustic guitars.
It's still possible to get Brazilian (lower-quality Brazilian) at a high price, but the luthier has to have a lot of paperwork showing that the wood came from a tree cut down before 1992. That era of getting Brazilian from old stumps is an era that's pretty well passed, however.
Madagascar Rosewood was illegal to import (under Madagascar rules, I believe) for years, but a coup made it possible to get some into the country over the last decade or so. It's the closest thing, tonally and in looks, to Brazilian that we've seen.
East Indian is nice, but nothing like Madagascar or Brazilian Rosewood.
All of that is said with respect to using the wood as a tonewood, and not just as a fretboard or the veneer on a headstock.
And using Franklin Titebond instead of hide glue makes a difference, I believe. Think of pulling away old white glue. It still has a rubbery feel to it. Hide glue is brittle. When you want to transfer vibration from one wood component to another, rubbery white glue, no matter how well cured and now matter how thin the coat, dampens the vibration. That's what I hear from luthiers and based on guitars I have that are made with hide glue, I believe I can hear the difference.
Horrified at Torrified? Or the Horror of Torror?
These being electric guitars, the wood surfacing of the fretboard would seem to have precious little to do with how they sound. But I’m sure when ivory gave way to bone and plastic for the tops of piano keys, pianists were horrified for similar reasons, or non-reasons.
“In short, putting a Torrified maple fretboard on a Les Paul will undoubtedly result in mountains of angry letters from Gibson players!”
Better not tell them about the Les Paul Raw Power Studio model, then. That has a rock maple fingerboard, and while it looks like it’s been tinted a bit it’s still almost as light as one on a Fender guitar.