I agree with rusty46, I don't think that they were not an option. I have seen modified mirrors on them, mostly header mounted. If you try and mount them like the AD trucks you will have to consider the opening of the windshield. The AD trucks are fixed windshields. Those AD's that came with mirrors had the center trim bar designed with a threaded bolt hole in them.

I remember the old Triump TR3 having their's mounted on the dash, they were taller than most mounts, something that you would have to consider with the high rear window.

Here is an option that might look good on your's with some modifications.

oval mirror