I NEVER put used electric chokes on carburetors that we build here.
They go bad with time, and don't heat up effectively, so you will see different results testing them as far as release time. I also suppose the factory varied the release time some based on application, especially with the later ones that were set up to be not adjustable.
I used to test the used one and put them back in service to save the customer some money, but that deal bit me in the backside too many times, so they all get replaced.....Cliff