Help identify Springs

[KW-Duster]

Seeing if someone can help me identify springs I took off of a 71 Duster. Both springs are 6 leaf and have the number 3722292 stamped on bottom leaf. There is also three rows of numbers in the center 717 65 2412

Thanks.

 

[Veryfastdart]

340 leaf springs

 

[KW-Duster]

Thanks. Is there a way to tell what year they might be from just curious Car was originally a 340.