Good to see another Caracal Cat owner (and with a 140 also!). The earlier 255 Tom Cats, had all wood in the interior. Also balsa core in the hulls, although the foam was n the transom fairy early.
I am not certain what year the molded interiors came along--they were present probably in the 2009 era, certainly by 2011. I cannot comment as to when the Balsa was completely eliminated from the core of the hull. Boat construction occurred periodically, but not by "model year"--ie some 2005 would have 2006 changes, and some would be more like a 2004.
If the core is kept dry (no screw penetrations), there are some good reasons to use balsa over foam. Even with foam, the core should be sealed off. If moisture gets into a foam core, and there is freeze, expansion and contraction, then delimitation can occur.
Take a ride in a Tom Cat, if you haven't already. Great cruising boats, but they are going to be a little different than even your Caracal. Bridge or wing deck is a bit lower to the water. I consider both the Caracal and Tom Cat to be planing cats.
I had a chance to look at a brand new Tom Cat at Hontoon, provided by 3 Rivers Marine. Nice boats, and some features which are improved over the earlier 255 model I owned.
All in all the Tom Cat 255 has proven to be a trouble free boat.