Another weird thing regarding this, I just did duplicate this in TA, after you do the disappearing thing with backspace 2x, you hit 1 to get to pilot position and I noticed if I fired my guns they were shooting from the rear tail gun.
We may not have noticed that with external view off during KOTH but in TA with it enabled it was clearly showing tracers from rear gun when firing from cockpit after you did the no rear ammo double backspace thing.