Assuming that the C.ofG.is in the right ball park(very little down stick inverted,just a very slight drop after a half roll to inverted on a 45 degree up line), the model will attempt to climb when flying upright.
Thus,to achieve a level flight path,upright, down elevator trim will be needed.
This in turn will mean that, on a level flight path, the fuselage will look "wrong", processing along with its nose down and its bum in the air.
(I am nearly old enough to remember a just pre-WW2 British bomber which flew like that---seen the pictures though)