I haven't seen much up close photos or recalled them in recent memory to know but I think that the 20A might share the more refined manufacturing processes like the J-35 which has lesser the number of panels and smoother surface and with that will come a newer RAMI recall the LRIP J-20s also had a darker skin at the start and skin became lighter as they left that stage.
Would be interesting to have a return to darkness on the 20A/S, more intimidating for sure![]()