Found small damage as shown. Should be an easy repair. Is this common to happen?

I bought this small Train collection at least 10 years ago. Much is in New opened Box condition. Some assembled. Check My other items currently for sale if interested in other modeling train components. Im listing these in NEW condition as these items in many cases seem to have not been assembled, or used. In the off chance the condition is not correct, I have attempted to provide accurate detailed photos so you might draw your own conclusion. While shooting the photos of each item I have noticed the metal components have started to show some corrosion. These surface issues are generally caused by oils from fingers during the packaging and subsequent assembly. Those parts are removable for cleaning or detailing and can be cleaned back to like new. Several kits have as expected several small parts included. Since I am not verifying completeness due to lack of knowledge, these same photos will show all included pieces, and paperwork. I'd love to ship several items to you in one package but since I am offering free shipping it wont make any difference in price. Please review the photos and ask questions if you have them. I don't offer returns. Items will be securely packed and shipped for safe delivery.