Shims behind the upper control arms???

[COBALT]

So I got the lower control arms off, and the springs out, and I'm about to bang out the upper ball joint, and pull the upper control arms. I noticed on one side I've got these thin wierd shaped pieces of metal behind one of the upper control arm assemblies. They look like shims. What gives? If I'm replacing everything do I really need to worry about those shims? I'm going to clean them, and keep them in the right order in case I need to reinstall them, but I have no idea why you'd need them there unless your spindle didn't line up correctly, or an incorrect part was used and this was a solution to making it fit....

Any ideas?