Here’s a very informative discussion regarding original jack designs that I stumbled upon during my quest for my 12B ‘69 Z/28 -
http://www.camaros.org/forum/index.php?topic=13242.0
Ultimately, I found LOS and VN cars had the Walker style jacks. I had quite a bit of difficulty locating one. One day I decided to ask Mr. Stubbings, via facebook messenger, of heartbeat city if he had one since he deals with a lot of used/nos camaro parts. Luckily, he did and it was a beautifully restored complete assembly. Might be worth a shot to give heartbeat a call in the morning.