I have the De Havilland D.H.4 (Atkey) and i noticed that on the base and card it says B/A for its guns. But on the model it has twin guns in the front and a single gun in the observer spot. I've been playing that the the card is right but i was wondering if anyone knows for sure.

The card is correct. Several of the minis show the wrong gun types. This is because they use a single model to represent all the different card versions of that plane.