Not sure why it would need to be perked ords, its not an unusual loadout, the mission dictates the ords carried for a mission, P-38s were well capable of carrying the ords and have in combat missions.
If P51s can fly with rockets and bombs, the B-38 should be allowed its ords package too.
If were going to start perking the ords, then I would agree, give the P-51D 2 perks if it carries bombs and rockets, or no perks for just rockets or bombs. What this allows is if someone in a 109G6 catches a P51 with ords, the person would be given a ton of perks over it.
With ENY i've always been arguing we need to have perked ords/gun packages, nothing wrong with taking 6x 500lb bombs, it wasn't a prototype and it was used in the war, however it wasn't always used, it was one of the more unusual setups for a plane.
Hell i'd be golden to perk the C.205 and let it have drop tanks (they did carry them, it was simply not really needed due to defending italy). It wouldn't be much, maybe 1 or 2 perks at the most.
Some will argue "well new players don't have the perks, so we are limiting them". Well, they can just as easily fly a higher eny plane like a Ki-84 and gather some perks, shooting down perk loaded aircraft would give a few extra perks.