I don't find factory errors appealing at all. I buy model representations of locomotives, not factory mistakes.
The yellow pin stripes were missing on the left side of this Flyer U33C...
I immediately sent it back to Lionel and they replaced it. (Although it took 3 months because the parts hadn't caught up with the production units...)
A year later, lightning stuck again, this time on the CC passenger set...
Back to Lionel for replacement. This time it only took about 2 weeks for the replacement to show up.
Rusty