Replacing front overhang window in 2009 Class C

You are right to assume problems. If you have had water, you could have dry rot. That robs structural strength. Or you can have wet rot, and sealing it in is even worse. If you have had water around the window, water settles to the lowest point, so it could creep to the bottom of the overhang, then it flows to the overhang corner and down.. Don't ask me how I know this. Usually, if you have noticed water on the inside, it's a lot worse than just a local problem.