I was told by a previous owner my car had cowl induction on it originally. I have the hood still on the car and remnants of silver paint under it exist which is the factory color. The hood appears that there was screws in the holes where the flapper would be mounted. It has a bracket/hole on the throttle rod for the switch to be mounted (did they all have it?). what other things should I look for as proof that it did have it? its a fairly well optioned car, rs, z28, tilt, guages, deluxe int, belts, etc.. so not out of place I wouldn't think and car build date is april 69 so it was available. thanks for the help!

The throttle rod has the mounting bracket only on cowl hoods. you hit on most of the things to look for. Also look for the hole in the firewall above the main wiring connector for the power to the fuse block, and a hole in the firewall on the pass side for the relay.