The Campbeltown kit does not represent the ship during St Nazaire. For that the ship was modified to more closely resemble a German torpedo boat. Grossly, the changes included cutting down the funnels. Royal Navy model guns were also fitted.
The Revell Campbeltown kit is of a non-modified 4-pipe destroyer. Had Revell chosen to release it under one of its other previous guises, that of the USS Ward - it would have been closer to the truth as to what is in the box
The Revell Campbeltown is pure 1960s state of the art. The decks are wooden planked. To accurately represent the steel decks of the prototype the deck fittings should be removed and the deck scribing filled and sanded. While you're at it, add some additional center-line height so that you can create some deck camber. Then replace the removed fittings.
The guns are clunky and need to have scratchbuilt replacements
Gold Medal Models makes a nice PE set which will go miles toward updating the kit
James Corley's build of the kit using GMM PE is on SteelNavy at http://www.steelnavy.com/ward.htm