That is correct.
Unlike the X3, which can be bought for $160-$200 and features a more mainstream market(I believe), the X5 would be more targeted towards those that would buy their own mSD cards.
It's not 100% confirmed, but there is a good chance the X5 will soon be able to support 256GB of storage.
Dual TF card ( Micro SD card ),
Support 256GB （128GB×2）Max.