I hope internally Blue Origin uses the metric system, it's been a long time since Miles per hour and feet were used to talk about rocketry, NASA learned this the hard way.
Falcon 9 is built on the imperial system, as are Atlas and Delta. SpaceX is only switching to metric with BFR.
Getting them mixed up sounds potentially risky. :/
Definitely would expect they've added some automatic safety checks around that, which is quite do-able in NX from memory.