SmtpClient - Email Timezone Issue

I'm having a strange issue with email timezone when using the SmtpClient and the receiver is a gmail customer. I'm not sure if it's gmail only, but this ONLY happens when I use this class for my SMTP send.

1. I have a web app running on IIS on a server in CST
2. At 9:30 EST it sends out an email to a gmail address using SmtpClient.Send() and no filled-in date fields of any type (are there even any?)
3. I open the email at home, EST, and it reads "1:30 pm" and hours later claims to have gotten the email (0 seconds ago).

Other things we've tried:

1. Send SMTP by hand over the same SMTP server to gmail..timestamp was correct
2. Send SMTP from a node.js library (nodemailer) over the same SMTP server to gmail..timestamp was correct

Are there any hidden less-documented pieces that might explain why just this library is ending up with wrong timestamps?