For certain the lower control arms are not from an 88, the shock mounts thru the middle of the coil spring on 88's. The look like 84-87 LCA's but even the 84 LCA is slightly different that the 85-87 LCA's although they will interchange physically.
The 88 front crossmember has slotted holes for the upper control arm cross bolt to attach. There is also a paddle plate that keep the nuts from spinning on the bottom side. To adjust, just loosen the bolts and move the upper a-arm to where it needs to be, then tighten. Any adjustment to caster also impacts camber, so it takes some finesse to get it right. Here is a picture of the slotted holes (from Blooz's thread):