I don't know if it's gonna end up being a shop or event exclusive. It's hard to predict based on the info I have. Sendai shop reopening in scheduled for the end of May and they will probably have a Renewal Fair. And Laforet is likely going to have something to make up for the GW event that never happened. Maybe it's reserved for one of these events.
For some reason white, pink and black colourways of LBS were ready earlier than yellow. They planned to start selling the first three colourways as early as April 24 (Laforet Golden Week event). But not yellow, the most anticipated colour that was on the look book cover. And we're only getting it now, on May 8.
So maybe (warning: speculation on my part) the fifth colour is also delayed by the factory or someone else in their supply chain.>>10608610
It's not a new LBS cut if this is what you're implying by "special set".>>10608625
In this case I would recommend to wait. I don't know how easy to get it will be in case it ends up being a store or event exclusive. So keep this in mind when deciding whether to buy this week or not. Do you have a preferred cut?