Yes, for vehicles that were designed to have them and in certain exotic applications.  For example, some vehicles such as Toyota 4×4 trucks and 4Runners have front springs with different arches and heights on the left and right.  Yet some spring companies make identical front springs and expect you to use a block or shim plate to make the truck sit level.  However, in all such left/right cases, Alcan Spring makes the correct left and right springs without ever relying on blocks or spacers.