Is it necessary to replace my Pixel motherboard? Please help!

Hi,

I was facing the issue of Pixel not charging occasionally. I gave it to the service center as it was under warranty. The service personnel says that he can see some small rust bits on board (refer images below) and thinks water has damaged the part so the motherboard needs to be replaced and it will cost ~ $460. I was not facing any other issues other than occasionally not charging.

Here are the photos https://goo.gl/qCEHJP

Do you recommend I go ahead and change the motherboard? or daughterboard? Please help!!

Thank you.