i don,t think it really matters that much with the thickness of the flywheel as if it is shaved down , the clutch / pressure plate will only move abit closer to the gearbox and if there is any adjustments needed you should be able to adjust the clutch peda rod to take up any free play from the slave cylinder.
i am sure the machine shop guys would know if its to worn down for any machine work, maybe take the flywheel in to them for a look. thats if its off the engine.