Two diff slave cylinders for only the 1990?

My slave cylinder is dead.... Why is there 2 diff save cylinders for the 1990 and the last 6 of my Vin dosent match either if the Spec vins listed for the the slace cylinders. Then in 1991+ this dosent matter. I'am getting this from autozones website.
Thanks guys

Yes, there are 2 diff. ones for a 1990 model. Don't know why, but there are.

1991-2005 all use the same one.

If the last 6 digits of your VIN are 111969 or less, it's one.

If the last 6 are 111970 and up, it's the other

thanks bud!