This may be an entirely moot
discussion, but I'm fairly certain in that period, "silesaurs" would
have probably been lumped into Ornithischia based on some (likely
convergent!) similarities. :-)
And then used to argue that Saurischia is descended from Ornithischia rather
than the other way around!
Or perhaps they'd have been called prosauropods simply for being "primitive
dinosaurs".