[BonzoHansen]

Am I reading this wrong?

Marks from 1966 through December 1968
Transcriptions of three different examples of the variations of LOF OEM glass markings are seen below in their pre-1969 version (e.g., without the DOT mark). Note that "date/plant" is not literal but indicates the location of the Date and Glass Plant code discussed later. See also the later discussion of marking details, such as hyphen use.

       SAFETY  L    PLATE
          AS2   O   date/plant
                 F
          SOLID TEMPERED
               M51

LOF Date/Plant Code
The LOF date code is rather-well known in Camaro literature, but is included here for completeness. It is a two-letter code, a one-letter month code followed by a one-letter year code, as shown below. For example, a code of NX is interpreted as January 1968.

1966-1970 LOF Glass Dating System 
                 LOF Month Code - First Character
           N   X   L   G   J   I   U   T   A   Y   C   V
          Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

                 LOF Year Code - Second Character
   A    Z    X    V    T    N    Y    U    L    I    C    G    J
 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 
 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978
 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991

LX = March 1968