The IP of the proxies on the TOR network can and do get blacklisted/flagged as spammy. The entire list of TOR nodes is public. For example, here's one copy of the full list:
https://www.dan.me.uk/tornodes
Although, it's important to note that your IP address isn't necessarily relevant to getting email spam into someone's inbox. The recipient doesn't necessarily have your IP address; they (generally) have the IP address of the server of your email client. It should be noted that whether or not a recipient has your IP address information depends on what email client you're using and how they've configured their headers:
https://www.whatismyip.com/how-to-trace-an-e-mail-address/
TOR isn't necessarily a problem for email spam (although it can be), but it's not a complete solution, either.
