1983 El Camino Trim Tag, Line 4?

[DSRTDWELR]

Hello, I am new here and need some help. My issue concerns a 1983 El Camino. I have decoded the Trim Tag first three lines with no hassle, thank you. However Line 4 contains two codes, they are:

12

3159

Have not been able to find a clue. Can anyone help? Thank you.

[melloelky]

have you tried looking in a Chilton's manual?there is a lot of infomation to be had in those on these older cars.

[bubbameano]

I think those extra numbers on the last line are factory sequence numbers that mean nothing once it leaves the factory.

[oldtinsmith]

Haynes manual says they are "plant use" options.

Doug