Most of the rumors will say that, yes, but I think he has to say that. By saying "I want to be a free agent" he's really saying "pay me like a free agent". If he says "I' am open to an extension" it says "I'd be willing to take a discount" to some.
The messaging from Tucker and his camp will almost assuredly continue to be that. The Cubs will continue to say they see this as a 1-year trade, largely because we have to separate trade from extension. I do contend that the Cubs wouldn't move these kinds of assets without any thought that an extension was possible, or that they were so out of touch with reality that they don't understand what his market value is. They most likely will attempt to engage him and his reps during the next few months on seeing how well they can work towards a market value extension.
Overall, it's probably fair to assume the most likely scenario is that he'd be here for one year. But that we can also be logical and understand why he's saying what he's saying, and that the team is probably not doing this with an eye on just one year, too.