If you are like me, a $25 kit vs. a $100+ ready built makes me pause before making the ready built look old and beat up. To back this up- I have not yet (gulp) weathered my new Legacy F7 set ($800) but I immediately weathered the Pennsylvania Flyer starter set locomotive (set price $ 239- loco value, maybe $ 100) I just got from my son. And it takes a dedicated hobbyist to take a bottle of india ink/ alcohol to (say) a $ 2000 Legacy Niagara.
Every time a visitor comes they think "weathered" is cool.
From your pictures- it all fits and looks good- I wouldn't change anything. Also- remember in the real World, people paint, sand blast, tuck-point buildings, making old ones look new.