Welcome aboard!
The fender mirrors are a great look, and original to that car. From what I've read, they were installed at the dealership, so there is no "exact" place where they mount.
I'd keep them for originality's sake!
On their death bed, nobody ever said, "Gee I wish I'd spent more time at work!"
'68 Sprite 1275
'76 Midget 1500