Actually there probably would be weathering in space. To join the panels and make them airtight, youd need to use a grease, or glue of some type as well as welding the plates together. However, Anytime you came near a star (ie, entering the solar system) the ships would heat up and the panels would separate slightly. Then when you leave, they would shrink again. This would leave behind marking and weathering. And if it was a full time space vehicle (which it would have to be judging on the size of it) it would very rarely get cleaned. And also if it was a combat vehicle, this would also produce scarring and marking.
Sorry, just thought id say something about how i think the weathering is accurate lol.
It looks good, i like it.