[RRGuyNJ]

You are 100% correct. Unfortunately the walls are already closed in so we have no idea what's behind them. The way I understand it is if you buy a "Spec-Home" you don't have much say over what goes on and can't be on site watching the build as you can in the outside world. I certainly hope if it's a custom built home the owner can be on site to see how things are progressing.
Your photo shows what should be an onsite crimp done during installation for the flex vent to attach too and the connections are opposite within the wall and going with the air flow as you described. That crimp appears to be a factory crimp and could be a male to male adapter as mentioned earlier. In the end, who knows? Maintain it by cleaning it every few years with a rotary brush and a shop vac and you should be fine
Good luck with your move.