7-200-9-019
YDDDYRRR
YY is the production year
DDD is the day of the year
RRR is the factory ranking/plant designation number.
Prior to 1984 when the Kalamazoo, MI factory was closed, the numbers 001-499 indicated Kalamazoo production. Ranking numbers 500-999 continued to indicate Nashville production through 1989.
Year 79
Day of the year 1979 "200" so "19 july 1979"
Rank number 019
So it's Kalamazoo production 'cause numbers is between 001-499.