Rear view mirror alernatives?

[archtech]

Got a '71 longhood that I love to drive it. I love the classic's small bumpers, the silver targa band, the nice touches of silver and black on the backdrop of the body color. While driving though, looking at the rear view mirror and touching the hollow plastic body does not give the level of respect I think the Porsche should have. I'm toying with the idea of using an earlier one... from a 68 or earlier. Anyone every done this? I'm just not sure of the mounts.... 68 was breakaway and 67 had 3 screws... which fits my car? Good idea? bad idea? thanks!