Below are 88 caliper images. The caliper housing and bridge appear to be made from different metals.
I think all pre 88-Fiero caliper housings were aluminum. Just read all the posting about stuck bleeder screws caused by dissimilar metals. The brake recall bulletin even mentions the aluminum caliper housing/steel bleeder screw problem.
However, both pieces on my 88 calipers seem to be made from cast iron. Oddly there is no rust on the bridge piece but there is on the caliper body so the metals are somehow different. (edit to correct info)
[This message has been edited by spark1 (edited 07-24-2004).]