What's WRT?

Fwiw - the pieces that bolt to the body are the stanchions, the pieces that are mounted on top of the stanchions and accept the windshield frame studs are the posts.

Is it the spacing that's incorrect or the windshield post angle does not match?

A little grinding on the stanchion stop area will allow an angle match for the posts.

Deuce is correct on trying to match the spacing between windshield posts and windshield frame.
A friend of mine has built a whole bunch of Deuce roadsters over the years and he has yet to match the vertical gap on the sides.

The Deuce is what it is....