Likely more cosmetic than structural. Common to find cars with alterations like this, either where the spring bucket has been welded to the underbody, or some kind of subframe connector was welded in (I've seen both in cars used on the drag strip). Shouldn't be a big deal if that is the case, remove the remnants of the welds and/or replace the spring eye buckets with good used or reproductions.
Regards,
Steve
