Welcome! What a great boating town/area you hail from :thup
My guess would be that it was simply an adjustment to the figures, not any real weight increase. And even then, I'd somewhat take it with a grain of salt, as the figures tend to be low.
I can't think of any change that would have suddenly added ~225# to the hull itself. I don't know what that figured is supposed to include, but if it theoretically includes the engine, it may be a reflection of the fact that by that point in time, most folks had changed from a ~250# two-stroke to a ~400# four-stroke (if engine is included in that).
If you are wondering about trailering weight, I'd probably count on 5,000# all-up. You may come in a little lighter, if you pack light, or have an aluminum trailer, but I wouldn't want to NOT count on that much. I have weighed numerous times and usually come in around 4,600#, including tongue weight.
Of the dozen or so C-Dorys I've seen up close (ranging from 1990 to 2009), I haven't seen any substantive changes in quality or build. There have been some feature changes over the years. You might prefer one era or another for its particular mix (I like the early 2000's, so that's what I looked for). That said, by the time a boat is more than a couple years old (and on up to decades old), it's mostly about care and condition, to my mind. (Presuming consistent build quality, which I'd say the C-Dory has in general.)