sportwagon

I am decoding our "new" 1966 Sportwagon and cannot find info on some of the codes. The Div. Series number is 44455FL1 which I know is a Buick Sportwagon with 2 seats, but what is the FL1? Also, under the trim code are the letters WCFR 2KX and under those numbers it reads 4F 5Y. Can anyone tell...