As long as Lucid says that it is fit for a particular purpose, they really have no choice but to send you the whole package, unless they tell you before you purchase it that a trade in is required, so I wouldn't expect any surprises. I don't know how many people had compatible equipment prior to this going on sale, or if indeed anybody got a car with compatible equipment at this stage., and if they did, whether they'd get something different. But I could see somebody with compatible equipment feeling cheated by getting less for the same money. Nevertheless, Lucid is advertising the connector only, so nobody could claim that Lucid sent anything less than was offered if they send only the cable in the future to customers who don't need new compatible equipment for it to work. And they could, at some point in the future, say that it requires equipment with the logo. If they asked for a trade in in the future, it wouldn't be unreasonable, but then Lucid would have to decide what to do with the returned units. They could be used for warranty exchanges, assuming they are undamaged, but it might be more trouble than it's worth.
What surprises me is that Lucid doesn't offer the kit by itself without the RangeXchange connector in the online store. I could see people wanting an extra, if they use one at home and feel that the dedicated one is overkill.