Yeah this looks like a reapplied sticker most likely done by the seller, no HiT Toys sticker I don’t think has a perfectly cut out outline like this, a real sticker for a HotR Talking Thomas looks like this:

As you can see the sticker on this one’s got a much thicker red outline on the boiler, and the cab door detailing is a liiitle bit different, as the one you’ve got TTF doesn’t have that small black line near the top of it, while the boxed one has it. It also has a strange off-shade to it too, but that’s probably from the printer the seller used for this discoloring it a bit.
So that’s my take on this, being that it’s just a sticker that was run down over many years and reapplied on again by the seller. You might need to do that with the window sticker too, it’s hanging on for life up there lol! Rest of it looks good too btw.
Also thought I’d tack on the fact that the coupling in between the Thomas and green coal truck also was most likely redone by the seller, as I realized not too long ago that the coupling actually cannot be easily swapped out without having to fully unsolder and solder the wiring inside the motor, so you can slip a coupling in and out for replacement. So if you’re gonna replace it, just be careful when doing so. 😉