CASTER CAMBER PLATE QUESTION

[gtcobra302]

What is the difference in a set of cc plates for a 93 GT and a set of cc plates for an 89 GT. Can I use the cc plates off of a 93 on my 89? Why are the year specific from 79-89 and from 90-93 in all of the ads for them?
Thanks

 

[KDK1988GT]

I did not think there was any difference...