If you look at the exterior, and there are storage doors
on both sides and/or water heater access underneath where the twin beds would be located, that is a sign the trailer has the twin layout for sure. Not all twin models have exterior storage located under the beds, but many do.
In the queen models, the area on either side of the bed has a very narrow asile so you can walk around the bed, and so there is no storage installed there. AS instead puts all the storage underneath the bed and installs lift struts so you can access the storage from the top as well as the side of the bed.
If there are exterior storage doors only on the driver's side, that could be a queen layout with the bed oriented sideways in the coach, with the access to the bed around the curb side and rear. In this layout you will be able to see that there is no exterior storage door in the rear above the bumper.