My block is a 2000 and the cover came off my 98 block and I didn't have any problem. But if it makes you feel better pick some up they won't be expensive.
The ABS ring looks like a cogged ring, that runs on the around the axle. To be honest with you I'm not sure it can be out of alignment, but something may be wrong with it.
You can get a complete kit and any little insghts you need from Randy Stinchcomb at Liberty Ford 410-655-2000. His prices are very good and he not only sells stang parts he races his mustang.
http://forums.modulardepot.com/flyshow.php?&s=&showid=162
The first time I ran the wires to the sensor located on the side of the block I got higher readings because the wires contacted the header. I just rewired it and ran it along side the O2 sensor and it works with zero problems.