Their use varies. Some adhere to Kindig's system in his Golden Age book and others use them more loosely. It is most helpful for me if school names are geographically based. I recognize the tremendous variability in styling in any one place at any one time and over time. Compare an Isaac Haines to a Fainot and then a Valentine Fondersmith all made within 10-15 years of each other in Lancaster. Then unsigned early Berks County attributed rifles like RCA 18, 19, and 20 all made within 10 years of each other. So while we may see that in some schools (Lehigh or Bucks County), architectural clues are clear, in others, not so much.
