I think it is because your using 1.3 dynamo version. I am not sure if Rhythm pacakge nodes are updated to 1.3. May be the Author @john_pierson can put some lights on this.
Yep sorry @john_pierson. @tsandersin_tsandersi Are you using latest archi-lab package? If not install the latest archi-lab package that has been updated to 1.3 version.