Here is a photo of a 337B that was for sale jan/2021
Looks like he did without posts or plates.
Was it legal? idk.
I do remember reading somewhere the concern was that the windshield would/could pop out during flight.
but i think OEM wind shields were 1/8” thick at the time but now they are available in 1/4” and less likely to come out.
https://ibb.co/Fb85GrD