My Danner boots are leather, and Gortex, and probably have Nylon in them (Nylon is in the description of the new model boots at least). They are as near 100% waterproof as I've seen without going to full rubber. So I think a lot of it depends on how well they are assembled.
I don't recall which style mine are, but they look similar to those in the link below. Just to give you an idea.
https://www.danner.com/men/hunt/east...rown.html.html