I know a 'cheaper' RFL car and a more 'expensive' RFL car (sadly mine although if it were registered when it was made instead of 2 and a half years later it'd be in the 'cheaper' category!), and both are ULEZ compliant on the TFL website.

I don't know how the emissions are added for the V5 but it does seem they're the wrong way round. DVLA seemed to have issues with the descriptions of various cars, and as you can see from 'HowManyLeft' the model descriptions vary for the 260: ZT V8 260 (as per mine on the V5) and ZT 260 V8.

I can't believe emission figures are individually entered for each car, I assume when a car is registered they pick the car from a list and if one set are figures are wrong we end up where the OP is, although I'd have expected to have seen it before with the number of cars still out there (assuming possibly that 'ZT 260 V8' have the wrong emissions, there are 12 non-SE ZT cars on the road according to HowManyLeft's dubious figures).