Yes, I thing you are right about Lakewood come a bit later. Reason I use Lakewood as a reference is I have to have some sort of a Roll Bar to be able to test the car on the track. And Lakewood is early racing history, isn´t it? :)
All Lakewood 3 point I have seen, has the rear bar directed more to the left front spring hanger, rather than above the snubbe. That's way I also thing those who had some sort of a Roll Bar on this ´68-69 configuration custom made them.
On the other hand Lakewood offered several typ of Roll Bars for different car models. I don´t think I have seen one for the Mopar A-Body.