Let me get this straight...THAT flat end observation piece came from the 18" Al set Lionel offered in the 2015 VOL II? I'm blown away...do you have the specific 4 pack product number? Just curious...
I may have considered THAT set had I known...Alas, I'll keep my K-line sets...
As for paint, you may contact Lionel and ask for some 'touch up' paint. May be a PITA to get.
There's a lot of different shades of yellow and grey...like red....or any other color.
Good luck, keep this thread updated. Interested to see how it turns out.