(not OP, but I'll answer this as best I can)
Yes, stages 641-700 (and UX 1-700, etc) are playable with the mod.
1.x.0 versions of Pokemon Shuffle (such as 1.5.0) are downloaded from the eShop, and effectively act as the "base game".
In-between versions like 1.5.1 to 1.5.11 are instead...