I'm not sure but I think all A-500's were lock up. A-518 were either/or lockup/non lockup. If you don't want the LU function on a A-500 it can be disabled in the valve body.
When I was looking for info for the converter I bought from a member here for my a500
I have think it was "transtar" who showed an option for a TC that would work with the spline count of a lockup input shaft but that they "left the lockup clutch out of".