Story of my life.... As soon as I decided to ask a question, I find the answer.
According to the documentation (at the very end), there is a line that says I should replace my mount command with the following:sudo mount -t cifs -o sec=ntlmv2,username=something,rw,file_mode=0777,dir_mode=0777,password=********,nounix,noserverino //SERVER/Software/Games/roms/ /home/pi/RetroPie/roms/
That solved the problem.
I wonder however what would be the difference between this whole new line, versus your suggestion of just adding uid=pi to my previous line. Would you know?