Unfortunately it took a long time to hear back from my sys admin so my original thread was closed/locked. Thought it was worth posting an update.
Funny enough, the solution was very simple. I simply needed to set the port to 445 instead of 139 that I was using previously.
I was coming to rclone from pysmb, and in that package 445 did not work but 139 did, so I incorrectly assumed that would be the case in rclone was well.