The original Jag (and the ERA) use a subframe that determines alignment. The shims that you speak of are used to align the brackets with the non-adjustable holes in the subframe, so the arms aren't on when we install the shims.
You may be able to get an open-end wrench between the bracket and the pivot shaft. If you can't, you're going to have to figure out the shims necessary without the arms. I hope you kept the exact toe specs from the alignment shop.
