Maybe it's because they only wanted to show the certain weapon, so they didn't bother putting the upgrades on the other 2 weapons as they weren't shown.

I am assuming normal weapons will not be upgradeable, which bothers me. IF that is the case it would seem everyone will be focusing on Rare and Exotic weapons, drastically reducing that "customization" they wanted us to engage in. My hope is that normal weapons will be a resource for salvaging parts for possibly creating our own custom weaponry for looks purposes at the very minimum. But my real dream is being able to salvage all pieces from a gun and recombine to create a custom gun with custom upgrade trees. However that last bit is unlikely, as I can see the possibility for massive balance problems. But perhaps being able to scavenge pieces and then go to a station to perhaps infuse it with some standardized/accepted upgrade tree. Then we get a balance tested upgrade tree, but the joy of having a gun we designed and colored and pieced together over months of scavenging for that perfect barrel and magazine.