gibson sg faded worn

why has my gibson sg special have a blank truss rod cover?
bought a gibson sg special faded in worn cherry. have seen it on some pictures with a sg branded truss rod cover and in some left blank.think it was on gibson website it was left blank.
not really bothered either way. just thought it was a bit weird
not very helpful cos i dont know the asnwer but i got an ibanez with the same plain truss rod cover thing…. didnt affect the tone so nowt to worry bout lol
Gibson SG Faded, Fender Blues Jr. (Blonde) Clean