Correct Electronic Ignition box location on a 1971 Duster 340.

What is the correct location for an Electronic Ignition box on a 1971 Duster 340? I know they were points until mid model year, and then electronic was optional.
I've seen them all over the place. Some use one of the windshield washer bottle screws to hold down one end, but don't know if that is correct.
On a power brake car, there is a brace that bolts to the inner fender behind the washer bottle, so I doubt that it would be the correct location for the ignition box.
Thank you.