I honestly never gave much attention to the wiper motor setup at all. So I cant offer any more info. on that. It appears to be the original unit but as you well know, nothing is 100% on these old cars but the dirt, overspray etc. all appeared similar all around the firewall.
If it makes any difference, which I doubt, its an LM1 car too. 350/255, single exhaust, several options like am/fm flip face radio with single speaker in dash, fold down rear seat, power front disc brakes, a/c , vinyl top. Kurt, Mark and several others know my old car, current owner is looking to put in an LS1 over the winter.