I believe Frank Badalson makes exact reproductions of the cable, and the weird shaped E"bracket" assembly. His number is 804-743-0570 his parts are exactly as the factory made them. They are not the cheapest but accuracy is spot on.
If however, you need only the bracket itself I dont know if they include this in their inventory. I know a man that has many Challenger parts for sale and access to many more MoPar bodies. His name is Mark Hummer #419-236-4925 or
hummer@bright.net he has used parts and may be able to assist you. Eddie