Car windscreen glass has changed and evolved over the years, driven I suspect by safety legislation.
From experience, back in the 1970s glass was probably simply toughened. This is the stuff that shatters into granules.
Then laminated glass appeared, this is 2 layers bonded to a central plastic core. This is great as the windscreen never actually fails. But It was found that when a face hits this it can cause nasty cuts, even though the glass is glued to the plastic core.
Modern glass has the inner lamination made of toughened glass, so that an impact from the inside doesn't release and sharp bits.
So, what to fit in a 1970s car? I suspect whatever you like!
Simple toughened glass is the cheapest, but if it is hit by a stone you have no windscreen at all.
Laminated is fine, as long as you never face plant it....
Laminated/Toughened is the most costly, as screens have to be made to size.
