Ah! The bomb carriers were normally attached to the bombs first, then the whole lot winched into the bomb bay. However, if the model is depicting immediate post operation, then the empty carriers would still be in position in the bomb bay.
In which case the carriers would not be in the bay. I don't know but for some reason I love looking at dioramas but not so keen on building them. By the time I'm finished the aircraft model I'm usually keen on moving on to the next one so not much motivation to do the dios.
Think many of us feel the same Andy, for me putting the finishing touches to a model is a bit of a pain, I just want to get finished and move onto the next project.
But if the plane has Just come in, and the next load was in place to re-bomb, the carriers Would still be in the bay!
That's why there would be new carriers on the trollied bomb.