I recently purchased my 93 Allante and one of the most disappointing things with the car is the lack of a keyless entry system. GM introduced a keyless proximity system on the 92 Corvette and you would think that a flagship vehicle would at least rate a keyless system.
Actually, you could get one as early as 89, and probly earlier. But I know 89 for sure. I had it on my 89 Pontiac ASC McLaren Turbo Grand Prix. Althou I dont own it anymore, I do own a 90 version of the same car with KRE (keyless remote entry).