My first trainer was a RTF. From what you said, my trainer wing was the same way that the Nexstar is. A metal rod in the front and then 2 plastic straps with screws to hold the wing sections together. Let me tell you that is more than enough strength! When I finally crashed my plane for the last time, I flew it through trees. The wings broke off about 2 - 3 inches away from each side of the fuselage. When I recovered what was left of the fuselage, the center section was still rubber banded to the fuselage. I recovered all the parts, and after a thorough going over, installed them in the ARF version of my trainer. I am still flying that plane to this day.

That said, make sure that the wing sections are completely together without a gap before putting the straps on.