If the window is in backwards then the latch is on the outside. Is that the case?

I suppose if the frame was put in backward and the sashes installed with the latch to the inside... Most newer windows the sashes can be easily removed and I guess they could have done it that way. But they would have had to install the sashes from the outside instead of the inside. Hmmm I'd have to think about that for a while. I'm not too sure if that even possible either. Maybe more information would be helpful.

If they were installed backwards the screen would be on the inside and the sill would drain water to the inside of your house. Can you post a picture? I'd really like to see this.