Three M24 SWS variants appear in the game as separate weapons. The first one is the “SP-R 208”, chambered in 7.62x51mm NATO, returning from Modern Warfare, classified as a marksman rifle.
A variant chambered in .300 Winchester Magnum in an FDE chassis appears in the sniper rifles class as the “LA-B 330”. This is essentially the “ZLR SP-R Overseer” chassis from Modern Warfare. The name appears to imply that this is supposed to be a Long Action receiver, which is correct for the M24.
The “SA-B 50” marksman rifle is another variant in a custom chassis, which is the “XRK SP-LITE 208 Blitz” chassis from Modern Warfare combined with the buttstock of MW’s “XRK SP-TAC 208 Ultimate” chassis. Contrary to its name, which would suggest it is chambered in .50 BMG, the rifle is instead chambered in .300 Winchester Magnum.