Had exactly this thought, Stik. My LHS has some in stash. When I bought the kit I saw the box art and thought "Yeah, thats nice!" until the research progress started. Then I stumbled upon the pictures shown above and found it even more interesting.
Bad luck that my LHS really has NAVY nubers in stash (but no letters), but... theyre yellow and black. Of course you can say something like "Oh come on, the kit was only 16 €, so theres some € left for decals!" True! But I liked the challenge of masking them.
BTW - resaerching a correct font for it was tricky. If you ever need it, heres the bare facts for this spcial tail section speaking for 1/48 scale:
Font: "US NAVY font" (too easy, eh?)
Size: 6mm high for the numbers, 8 mm high for the "5Z"