Wow! That sounds like some strangely serious damage there jkruse! Got pics? ;D
To partially answer your question, at least as far as the dash is concerned, it will physically bolt up, but some of your switches and wiring will differ and may need to be modified to work.
You'll also lose your nice dash indicator light bars below the control knobs.
You may also end up with extra holes, such as the one for the hazard flashers. Your '74 would have the hazard switch in the steering column, while the '67 would have it on the dash.
The knobs are different and the speaker location may be different as well.
So yes, it can be done. But no, it's not just a bolt-n-go proposition.
As for the windshield frame, I believe that they are all the same basic size and shape, but here again, some minor variations may not keep you from finishing, but they'll add a layer of hassle that might be better taken care of by finding another donor from a '74 through '77 rig.
The early one may bolt on, where the later should be welded at the hinge.
The wiper pivot shaft hole locations are different.
If the early has the hold-down clamp, it may only be a visual issue. Should not keep you from mounting things up I wouldn't think.
Anyway, good luck either way. Would like to see pics of what you're describing sometime too.
Paul