We should view the fraternity through the lens of that time period versus our own concept in 2020. Before 1920 there did not exist the concept of Undergraduate or Graduate Chapters. It was just chapters. Also, there did not exist the term UG or Grad brothers as well. The only delineation are brothers initiated in a chapter or their elected members. Remember that prior to 1920 we had only five sources (chapters) into which brothers joined the fraternity: Alpha, Beta, Gamma, War Chapters at Fort Des Moines and Camp Howard. Alpha, Beta, and Gamma could have both initiated and elected members in their ranks with the latter typically having earned a college degree.
For the War Chapters, brothers could have completed their UG studies and were still initiated into the fraternity. Those members, after returning home from their overseas service or released from active duty, could have affiliated with the chapter at their campus where they matriculated, chapters at their graduate school, or in some instances chapters where they taught. The key is that the War Chapters provided the first opportunity for men to be initiated into the fraternity outside of a college campus and who already earned their degrees. In the fraternal lens of that era they were not viewed as anything else but initiated brothers.