To me that looks like a 16 Hourston hull. I am not an expert but the 17s I have seen have a lower chine at the bow, and the strakes are arranged differently. The chine on that thing comes up fairly high compared to where the waterline would be, and the strakes are pretty much longtitudinal, which says 16 Hourston to me.
The 17 DEs I know have a similar chine location, but the strakes look more like the Hourston 17s.
Granted I am only speaking from the hulls I know; I don't know if they always used the same moulds. But if you google Hourston Glascraft 16, you will see what I mean: look at where the strakes intersect with the chine, and the chine intersects with the keel.
Not definitive but that's how it looks to me.