I have exploded view diagrams of the two types on hand from a dealer. The easiest way to tell is by looking at the tie rods and boot covers. On the ZF rack, the outer end of the boot (the side towards the wheel) clamps onto a large bushing (some brickboarders refer to the same as donut) which in turn is on the tie rod. In the Cam rack, the outer end of the boot is clamped directly onto the rod.

Another way to tell is the Cam rack has a huge plug looking thingy at the top of the gearbox of the rack and the ZF doesn't.

If you have a fax machine I can fax you a copy of each type, although I am not sure how the quality will be since I would be faxing you a copy of a fax. The quality of mine is kinda streaky as it looks like the guy at the dealer took it off a fiche or something.