89 was the first year, if I recall, of the ZR1.

im pretty sure 90 was the ZR1, and only 90 ZR1s got the squared off taillights(84-90 were round), then in 91 all the vettes got the 91-96 style taillights.


**EDIT**
Al, we are both basically right, there were 80 ZR1 package 1989 vettes built, but none were publically available. 1990 was the first year the zr1 vettes could be purchased.