Lexan's just a trade name for polycarbonate.....It's great for high optical clarity needs and is pretty tough
(Motorcycle crash-helmets, most car headlights and the F22 cockpit "glass" are all made from Lexan/Polycarbonate)
It scratches at the drop of a hat- (CDs are made from polycarbonate- and think how easily they scratch!) and does have a habit of yellowing with regular exposure to UV light (and degrades in strength as a result)
It's also not very solvent resistant.
It also reacts badly to post-processing- like drilling holes and the like.
Personally, I'd stick with the engineering polymers that get selected for knife scales......
Warhammer 40000 is- basically- Lord Of The Rings on a cocktail of every drug known to man and genuine lunar dust, stuck in a blender with Alien, Mechwarrior, Dune, Starship Troopers, Fahrenheit 451 and Star Wars, bathed in blood, turned up to eleventy billion, set on fire, and catapulted off into space screaming "WAAAGH!" and waving a chainsaw sword- without the happy ending.