Simplex
2901-9806: 1976-1993 4903-9102: 1987-1995
2901-9833: 1977-1996. 4903-9101: 1987-1995
2901-9838: 1985-1997 4904-9001: 1987-1995
2901-9845: 1987-1997. 4904-9101: 1987-1995
2902-9739: 1979-1992. 4903-9105: 1989-1997
2902-9711: 1986-2001. 4904-9105: 1989-1997
2902-9732: 1983-1994. 4903-9217/9219/9220: 1994-2001
2902-9734: 1983-1992. 4903-9236/37/38: 1998-2009
2902-9234: 1979-1996. 4904-9731: 1994-present
2903-9001: 1977-1992. TrueAlert Series: 2001-Present, 2009-present for rectangular ones
2903-9002: 1977-1992. Quick alert series: 2000-2002
2903-9101: 1977-1992. TrueAlert ES Series: 2013-present
2903-9102: 1977-1992. 4251-1 chevron: 1958-1974
4251-20/30: 1970-1993. 2099/4099 pulls: 1992-present
4263 coded stations: 1960?-1980? 2099 metal pulls: 1992-2010
That’s all of the manufacturing dates I’ve gotten in my extensive research.
2904-9001: 1977-1987
2904-9003: 1977-1987
2904-9101: 1977-1994
2904-9103: 1977-1994