The HIN (Hull Identification Number) is virtually always located somewhere on the outside of the hull on or near the transom, but often also on a plate or secondary location as well. Shouldn't be hard to find.. The hull number will be part of that code.
Edited to add... apparently the H 40.5 has a 'hidden' HIN under the cover for the running rigging led aft. Perhaps they did the same with the 450. But I'd bet you'll find it somewhere aft outside..