When I asked the TH Boutique Customer Service they did not confirm the 3 months deadline.
If this would be true, I would consider this an unnecessary and unfair pressure on the customers, which for me would be a no go for this watch. When TH launched the Connected 46 they never mentioned such restrictions. I would understand on the other hand, if they would sell them in limited numbers, but not in such a narrow time window.
Maybe the talk about the 3 months is based on a missunderstanding? Maybe the restriction is only related to the spefic alternative options, which may change over time? Do you think, they would tell you to keep your 1,5k bucks and keep their watches in stock, since you are too late on their offer? Seems somewhat unlikely to me. But well, you never know.